Brown spider venom toxins: what are the functions of astacins, serine proteases, hyaluronidases, allergens, TCTP, serpins and knottins?

Accidents caused by the bites of brown spiders (Loxosceles) generate a clinical condition that often includes a threatening necrotic skin lesion near the bite site along with a remarkable inflammatory response. Systemic disorders such as hemolysis, thrombocytopenia, and acute renal failure may occur, but are much less frequent than the local damage. It is already known that phospholipases D, highly expressed toxins in Loxosceles venom, can induce most of these injuries. However, this spider venom has a great range of toxins that probably act synergistically to enhance toxicity. The other protein classes remain poorly explored due to the difficulty in obtaining sufficient amounts of them for a thorough investigation. They include astacins (metalloproteases), serine proteases, knottins, translationally controlled tumor proteins (TCTP), hyaluronidases, allergens and serpins. It has already been shown that some of them, according to their characteristics, may participate to some extent in the development of loxoscelism. In addition, all of these toxins present potential application in several areas. The present review article summarizes information regarding some functional aspects of the protein classes listed above, discusses the directions that could be taken to materialize a comprehensive investigation on each of these toxins as well as highlights the importance of exploring the full venom repertoire.(AU)

Design, synthesis, and evaluation of Bothrops venom serine protease peptidic inhibitors

In Central and South America, snakebite envenomation is mainly caused by Bothrops spp. snakes, whose venoms feature significant biochemical richness, including serine proteases. The available bothropic antivenoms are efficient in avoiding fatalities, but do not completely neutralize venom serine proteases, which are co-responsible for some disorders observed during envenomation. Methods: In order to search for tools to improve the antivenom's, 6-mer peptides were designed based on a specific substrate for Bothrops jararaca venom serine proteases, and then synthesized, with the intention to selectively inhibit these enzymes. Results: Using batroxobin as a snake venom serine protease model, two structurally similar inhibitor peptides were identified. When tested on B. jararaca venom, one of the new inhibitors displayed a good potential to inhibit the activity of the venom serine proteases. These inhibitors do not affect human serine proteases as human factor Xa and thrombin, due to their selectivity. Conclusion: Our study identified two small peptides able to inhibit bothropic serine proteases, but not human ones, can be used as tools to enhance knowledge of the venom composition and function. Moreover, one promising peptide (pepC) was identified that can be explored in the search for improving Bothrops spp. envenomation treatment.(AU)

Repertório de serina proteases como componentes do degradoma de Leishmania spp / Serine protease repertoire as components of Leishmania spp degradation

Esta tese faz uma abordagem in silico e experimental sobre as serina proteases de Leishmania spp. Na primeira etapa do estudo são descritas as serina proteases como parte do degradoma destes parasitos. Os genes de serina protease (n = 26 a 28) em Leishmania spp que codificam proteínas com uma ampla faixa de massa molecular, são descritos juntamente com seus graus de sintenia cromossômica e alélica. Em meio a 17 serina proteases putativas de Leishmania spp apenas 18 % possuem duas funções descritas experimentalmente como propriedades para remover o peptídeo sinal de pro-proteínas secretoras (clã SF), como maturases de outras proteínas (clã SB) e com atividades similares as metacaspase (clã SC). Análises in silico indicaram que o conjunto de serina proteases de Leishmania spp pode estabelecer interrelações funcionais com outras proteínas de Leishmania spp significando atuações essenciais na fisiologia do parasito. Padrões de redes distintos podem ocorrer e a complexidade destas redes difere entre as espécies relacionadas ao subgênero Viannia e Leishmania: Leishmania (V.) braziliensis (n = 215); Leishmania (L.) mexicana (n = 130); L. (L.) donovani (n=56) Leishmania (L.) major (n = 45); Leishmania (L.) infantum (n = 23). O fato das serina proteases de L. (V.) braziliensis indicarem mais possibilidades de interações com outras proteínas do parasito foi a motivação para segunda etapa deste estudo

Esta etapa consistiu em uma abordagem experimental e in silico investigando as serina proteases deste parasito, incluindo atividade enzimática de serina proteases de frações subcelulares obtidas por cromatografia de afinidade com benzamidina, reações em cadeia da polimerase com transcrição reversa e ensaios in silico de localização subcelular de subtilisinas. Promastigotas apresentaram serina proteases com atividade gelatinolítica na fração citosólica (43 kDa a 170 kDa) e na fração membrana (67 kDa a 170 kDa). Ambas as frações também demostraram propriedades de catálise sobre os substratos peptídicos N-benziloxicarbonil-L-fenilalanil-L-arginina 7-amino-4-metilcumarina (fração citosólica = 392 ± 30 mol.min-1 mg of protein-1; fração de membrana = 53 ± 5 mol.min-1 mg of protein-1) e N-succinil-L-alanina-L-fenilalanina-L-lisina 7-amino-4-metilcumarina (fração citosólica = 252 ± 20 mol.min-1 mg of protein-1; fração de membrana = 63.6 ± 6.5 mol.min-1 mg of protein-1) com diferentes perfis de especificidade demonstrada pela inibição com aprotinina (19 % a 80 %) e fluoreto de fenilmetilsulfonil (3 % a 69 %), dependendo da fração subcelular e do substrato. A expressão dos genes das subtilisinas (LbrM.13.0860 e LbrM28.270) e da triparedoxina peroxidase (LbrM.15.1080) também foram observadas, com a detecção dos transcritos de 200 pb, 162 pb e 166 pb, respectivamente. Ensaios subsequentes indicaram que a enzima codificada pelo gene LbrM.13.0860 tem localização no citosol e a codificada pelo gene LbrM.28.2570 na membrana do parasito. Coletivamente, os dados aqui obtidos indicam relevantes contribuições das serina proteases na fisiologia da Leishmania spp, incluindo as subtilisinas das promastigotas de L. (V.) braziliensis. (AU)

Subproteome of Lachesis muta rhombeata venom and preliminary studies on LmrSP-4, a novel snake venom serine proteinase

Lachesis muta rhombeata is one of the venomous snakes of medical importance in Brazil whose envenoming is characterized by local and systemic effects which may produce even shock and death. Its venom is mainly comprised of serine and metalloproteinases, phospholipases A2 and bradykinin-potentiating peptides. Based on a previously reported fractionation of L. m. rhombeata venom (LmrV), we decided to perform a subproteome analysis of its major fraction and investigated a novel component present in this venom. Methods: LmrV was fractionated through molecular exclusion chromatography and the main fraction (S5) was submitted to fibrinogenolytic activity assay and fractionated by reversed-phase chromatography. The N-terminal sequences of the subfractions eluted from reversed-phase chromatography were determined by automated Edman degradation. Enzyme activity of LmrSP-4 was evaluated upon chromogenic substrates for thrombin (S-2238), plasma kallikrein (S-2302), plasmin and streptokinase-activated plasminogen (S-2251) and Factor Xa (S-2222) and upon fibrinogen. All assays were carried out in the presence or absence of possible inhibitors. The fluorescence resonance energy transfer substrate Abz-KLRSSKQ-EDDnp was used to determine the optimal conditions for LmrSP-4 activity. Molecular mass of LmrSP-4 was determined by MALDI-TOF and digested peptides after trypsin and Glu-C treatments were analyzed by high resolution MS/MS using different fragmentation modes. Results: Fraction S5 showed strong proteolytic activity upon fibrinogen. Its fractionation by reversed-phase chromatography gave rise to 6 main fractions (S5C1-S5C6). S5C1-S5C5 fractions correspond to serine proteinases whereas S5C6 represents a C-type lectin. S5C4 (named LmrSP-4) had its N-terminal determined by Edman degradation up to the 53rd amino acid residue and was chosen for characterization studies. LmrSP-4 is a fibrinogenolytic serine proteinase with high activity against S-2302, being inhibited by PMSF and benzamidine, but not by 1,10-phenantroline. In addition, this enzyme exhibited maximum activity within the pH range from neutral to basic and between 40 and 50 °C. About 68% of the LmrSP-4 primary structure was covered, and its molecular mass is 28,190 Da. Conclusions: Novel serine proteinase isoforms and a lectin were identified in LmrV. Additionally, a kallikrein-like serine proteinase that might be useful as molecular tool for investigating bradykinin-involving process was isolated and partially characterized.(AU)

Functional and biological insights of rCollinein-1, a recombinant serine protease from Crotalus durissus collilineatus

The prevalent class of snake venom serine proteases (SVSP) in Viperidae venoms is the thrombin-like enzymes, which, similarly to human thrombin, convert fibrinogen into insoluble fibrin monomers. However, thrombin-like serine proteases differ from thrombin by being unable to activate factor XIII, thus leading to the formation of loose clots and fibrinogen consumption. We report the functional and biological characterization of a recombinant thrombin-like serine protease from Crotalus durissus collilineatus, named rCollinein-1. Methods: Heterologous expression of rCollinein-1 was performed in Pichia pastoris system according to a previously standardized protocol, with some modifications. rCollinein-1 was purified from the culture medium by a combination of three chromatographic steps. The recombinant toxin was tested in vitro for its thrombolytic activity and in mice for its edematogenicity, blood incoagulability and effect on plasma proteins. Results: When tested for the ability to induce mouse paw edema, rCollinein-1 demonstrated low edematogenic effect, indicating little involvement of this enzyme in the inflammatory processes resulting from ophidian accidents. The rCollinein-1 did not degrade blood clots in vitro, which suggests that this toxin lacks fibrinolytic activity and is not able to directly or indirectly activate the fibrinolytic system. The minimal dose of rCollinein-1 that turns the blood incoagulable in experimental mice is 7.5 mg/kg. The toxin also led to a significant increase in activated partial thromboplastin time at the dose of 1 mg/kg in the animals. Other parameters such as plasma fibrinogen concentration and prothrombin time were not significantly affected by treatment with rCollinein-1 at this dose. The toxin was also able to alter plasma proteins in mouse after 3 h of injection at a dose of 1 mg/kg, leading to a decrease in the intensity of beta zone and an increase in gamma zone in agarose gel electrophoresis Conclusion: These results suggest that the recombinant enzyme has no potential as a thrombolytic agent but can be applied in the prevention of thrombus formation in some pathological processes and as molecular tools in studies related to hemostasis.(AU)

Kn-Ba: a novel serine protease isolated from Bitis arietans snake venom with fibrinogenolytic and kinin-releasing activities

Bitis arietans is a venomous snake found in sub-Saharan Africa and in parts of Morocco and Saudi Arabia. The envenomation is characterized by local and systemic reactions including pain, blistering, edema and tissue damage, besides hemostatic and cardiovascular disturbances, which can cause death or permanent disabilities in its victims. However, the action mechanisms that provoke these effects remain poorly understood, especially the activities of purified venom components. Therefore, in order to elucidate the molecular mechanisms that make the Bitis arietans venom so potent and harmful to human beings, this study reports the isolation and biochemical characterization of a snake venom serine protease (SVSP). Methods: Solubilized venom was fractionated by molecular exclusion chromatography and the proteolytic activity was determined using fluorescent substrates. The peaks that showed serine protease activity were determined by blocking the proteolytic activity with site-directed inhibitors. In sequence, the fraction of interest was submitted to another cycle of molecular exclusion chromatography. The purified serine protease was identified by mass spectrometry and characterized biochemically and immunochemically. Results: A serine protease of 33 kDa with fibrinogen-degrading and kinin-releasing activities was isolated, described, and designated herein as Kn-Ba. The experimental Butantan Institute antivenom produced against Bitis arietans venom inhibited the Kn-Ba activity. Conclusions: The in vitro activities of Kn-Ba can be correlated with the capacity of the venom to provoke bleeding and clotting disorders as well as hypotension, which are common symptoms presented by envenomed victims. Obtaining satisfactory Kn-Ba inhibition through the experimental antivenom is important, given the WHO's recommendation of immunotherapy in cases of human accidents with venomous snakes.(AU)

Deep sequencing analysis of toad Rhinella schneideri skin glands and partial biochemical characterization of its cutaneous secretion

Animal poisons and venoms are sources of biomolecules naturally selected. Rhinella schneideri toads are widespread in the whole Brazilian territory and they have poison glands and mucous gland. Recently, protein from toads' secretion has gaining attention. Frog skin is widely known to present great number of host defense peptides and we hypothesize toads present them as well. In this study, we used a RNA-seq analysis from R. schneideri skin and biochemical tests with the gland secretion to unravel its protein molecules. Methods: Total RNA from the toad skin was extracted using TRizol reagent, sequenced in duplicate using Illumina Hiseq2500 in paired end analysis. The raw reads were trimmed and de novo assembled using Trinity. The resulting sequences were submitted to functional annotation against non-redundant NCBI database and Database of Anuran Defense Peptide. Furthermore, we performed caseinolytic activity test to assess the presence of serine and metalloproteases in skin secretion and it was fractionated by fast liquid protein chromatography using a reverse-phase column. The fractions were partially sequenced by Edman's degradation. Results: We were able to identify several classes of antimicrobial peptides, such as buforins, peroniins and brevinins, as well as PLA2, lectins and galectins, combining protein sequencing and RNA-seq analysis for the first time. In addition, we could isolate a PLA2 from the skin secretion and infer the presence of serine proteases in cutaneous secretion. Conclusions: We identified novel toxins and proteins from R. schneideri mucous glands. Besides, this is a pioneer study that presented the in depth characterization of protein molecules richness from this toad secretion. The results obtained herein showed evidence of novel AMP and enzymes that need to be further explored.(AU)

Heterologous fibrin sealant derived from snake venom: from bench to bedside - an overview

Hemostatic and adhesive agents date back to World War II, when homologous fibrin sealant came onto scene. Considering that infectious diseases can be transmitted via human blood, a new heterologous fibrin sealant was standardized in the 1990s. Its components were a serine protease (a thrombin-like enzyme) extracted from the venom of Crotalus durissus terrificus snakes and a fibrinogen-rich cryoprecipitate extracted from the blood of Bubalus bubalis buffaloes. This new bioproduct has been used as a coagulant, sealant, adhesive and recently as a candidate scaffold for mesenchymal stem cells and bone and cartilage repair. This review discusses the composition of a new heterologous fibrin sealant, and cites published articles related to its preclinical applications aiming at repairing nervous system traumas and regenerating bone marrow. Finally, we present an innovative safety trial I/II that found the product to be a safe and clinically promising candidate for treating chronic venous ulcers. A multicenter clinical trial, phase II/III, with a larger number of participants will be performed to prove the efficacy of an innovative biopharmaceutical product derived from animal venom.(AU)

In vitro characterization of jellyfish venom fibrin(ogen)olytic enzymes from Nemopilema nomurai

Background: Because jellyfish are capable of provoking envenomation in humans, they are considered hazardous organisms. Although the effects of their toxins are a matter of concern, information on the venom components, biological activity and pathological mechanisms are still scarce. Therefore, the aim of the present study was to investigate a serine protease component of Nemopilema nomurai jellyfish venom (NnV) and unveil its characteristics. Methods: To determine the relationship between fibrinolytic activity of NnV and the serine protease, fibrin zymography was performed using metalloprotease and serine protease inhibitors. The biochemical characterization of serine proteases of NnV were determined by the amidolytic assay. Fractions with fibrinolytic activity were obtained by DEAE cation exchange column. Results: NnV displayed fibrinolytic activities with molecular masses of approximately 70, 35, 30, and 28 kDa. The fibrinolytic activity of NnV was completely obliterated by phenylmethylsulfonyl fluoride, a prototype serine protease inhibitor. Based on amidolytic assays using chromogenic substrates specific for various kinds of serine proteases, NnV predominantly manifested a chymotrypsin-like feature. Its activity was completely eliminated at low pH (< 6) and high temperatures (> 37 °C). Some metal ions (Co2+, Cu2+, Zn2+ and Ni2+) strongly suppressed its fibrinolytic activity, while others (Ca2+ and Mg2+) failed to do so. Isolation of a serine protease with fibrionolytic activity from NnV revealed that only p3 showed the fibrinolytic activity, which was completely inhibited by PMSF. Conclusion: The present study showed that N. nomurai jellyfish venom has a chymotrypsin-like serine protease with fibrinolytic activity. Such information might be useful for developing clinical management of jellyfish envenomation and pharmacological agents with therapeutic potential for thrombotic diseases in the future.(AU)

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4-40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.(AU)

Proteolytic activity of excretory/secretory products of Cochliomyia hominivorax larvae (Diptera: Calliphoridae) / Atividade proteolítica de produtos de excreção/secreção de Cochliomyia hominivorax (Diptera: Calliphoridae)

The protein profiles and proteolytic activity of the excretory secretory products (E/SP) of the first (L1), second (L2) and third (L3) larval stages of Cochliomyia hominivorax were studied in the laboratory. Analysis on the E/SP protein profile was carried out using polyacrylamide gel containing sodium dodecyl sulfate (SDS-PAGE). The E/SP of each larval stage (L1, L2 and L3) treated with protease inhibitors, containing 30µg, 40µg and 50µg of protein, was applied to the 10% polyacrylamide gel. The proteolytic activity of the crude E/SP was analyzed in gels copolymerized with gelatin and by colorimetric assays using azocasein as a substrate, with the characterization of the proteases using synthetic inhibitors. Different protein profiles were observed for the larval instars, with L1 presenting the most complex profile. Nevertheless, various protein bands were observed that were common to all the larval instars. The E/SP of all the instars showed proteolytic activity on gelatin, evidenced by proteolysis zones, predominantly with apparently higher molecular masses in L1, while for L2 and L3 the proteolysis zones could also be observed in regions with lower masses. Tests with protease inhibitors using gelatin as substrate showed that the E/SP of larvae were mainly composed of serine proteases. Additionally, inhibition was observed in L2 E/SP treated previously with EDTA, an inhibitor of metalloproteases. The assays with azocasein revealed a gradual increase of proteolytic activity on this substrate with larval development progress, with the strongest inhibitions being observed after treatments with 3,4-dichloroisocoumarin (DCI) for E/SP of L1, L2 and L3. These results suggest that C. hominivorax larvae produce different proteases, a fact that can be related to the parasite's vital processes for survival, such as penetration into the host's tissues and nutrition during the larval stage.(AU)

Os perfis protéicos e a atividade proteolítica dos produtos de excreção/secreção (PE/S) das larvas de primeiro (L1), segundo (L2) e terceiro (L3) estágios de Cochliomyia hominivorax foram estudados em laboratório. Os perfis protéicos foram obtidos por eletroforese em géis de poliacrilamida (SDS-PAGE). Os PE/S de cada fase larval (L1, L2 e L3), tratados com inibidores de proteases, contendo 30µg, 40µg e 50µg de proteína, foram aplicados em géis de poliacrilamida a 10%. A atividade proteolítica dos PE/S na sua forma nativa, foi analisada em géis co-polimerizados com gelatina e por testes colorimétricos usando a azocaseína como substrato, com a caracterização das proteases feita por meio de inibidores sintéticos. Diferentes perfis protéicos foram observados para os instares larvais, com L1 apresentando o perfil mais complexo. Apesar disso, foram observadas várias bandas protéicas comuns a todos os estágios larvais. Os PE/S de todos os instares mostraram atividade proteolítica sobre a gelatina, evidenciada por zonas de proteólise, com predominância de massas moleculares aparentes mais altas em L1, enquanto que para L2 e L3 as zonas de proteólise puderam ser observadas também em regiões de menores massas. Os testes com inibidores de proteases usando a gelatina como substrato mostraram que os PE/S de L1, L2 e L3 eram compostos principalmente de serina-proteases. Adicionalmente, inibição foi observada nos PE/S de L2 tratada previamente com EDTA, um inibidor de metalo-proteases. Os ensaios com a zocaseína revelaram um aumento gradual da atividade proteolítica sobre este substrato com o progresso do desenvolvimento larval, com a mais forte inibição sendo observada após o tratamento com 3,4 dicloroisocumarina (DCI) para os PE/S de L1, L2 e L3. Estes resultados sugerem que as larvas de C. hominivorax produzem diferentes proteases, fato que pode estar relacionado a processos vitais para a sobrevivência do parasita, tais como a penetração nos tecidos dos hospedeiros e nutrição durante os estágios larvais.(AU)

Screening, production and biochemical characterization of a new fibrinolytic enzyme produced by Streptomyces sp. (Streptomycetaceae) isolated from Amazonian lichens / Seleção, produção e caracterização bioquímica de uma nova enzima fibrinolítica produzida por Streptomyces sp. (Streptomycetaceae) isolada de liquens da Amazônia

Thrombosis is a pathophysiological disorder caused by accumulation of fibrin in the blood. Fibrinolytic proteases with potent thrombolytic activity have been produced by diverse microbial sources. Considering the microbial biodiversity of the Amazon region, this study aimed at the screening, production and biochemical characterization of a fibrinolytic enzyme produced by Streptomyces sp. isolated from Amazonian lichens. The strain Streptomyces DPUA1576 showed the highest fibrinolytic activity, which was 283 mm2. Three variables at two levels were used to assess their effects on the fibrinolytic production. The parameters studied were agitation (0.28 - 1.12 g), temperature (28 - 36 ºC) and pH (6.0 - 8.0); all of them had significant effects on the fibrinolytic production. The maximum fibrinolytic activity (304 mm2) was observed at 1.12 g, 28 ºC, and pH of 8.0. The crude extract of the fermentation broth was used to assess the biochemical properties of the enzyme. Protease and fibrinolytic activities were stable during 6 h, at a pH ranging from 6.8 to 8.4 and 5.8 to 9.2, respectively. Optimum temperature for protease activity ranged between 35 and 55 °C, while the highest fibrinolytic activity was observed at 45 ºC. Proteolytic activity was inhibited by Cu2+ and Co2+ ions, phenylmethylsulfonyl fluoride (PMSF) and pepstatin A, which suggests that the enzyme is a serine protease. Enzymatic extract cleaved fibrinogen at the subunits Aalpha-chain, Abeta-chain, and gama-chain. The results indicated that Streptomyces sp. DPUA 1576 produces enzymes with fibrinolytic and fibrinogenolytic activity, enzymes with an important application in the pharmaceutical industry.

A trombose é uma doença patofisiológica causada pelo acúmulo de fibrina no sangue. Proteases fibrinolíticas com potente atividade trombolítica são produzidas por diversas fontes microbianas. Considerando a biodiversidade microbiana da região amazônica, o presente estudo teve como objetivo a seleção, produção e caracterização bioquímica da enzima fibrinolítica de Streptomyces sp. isolado de líquens da Amazônia. Streptomyces DPUA1576 foi a melhor produtora com atividade fibrinolítica de 283 mm2. Três variáveis em dois níveis foram utilizadas para determinar as variáveis mais relevantes na produção da enzima fibrinolítica (FA). Os parâmetros estudados foram agitação (0.28 - 1.12 g), temperatura (28 - 36 ºC) e pH (6.0 - 8.0) e todos obtiveram efeitos significativos na produção fibrinolítica. A maior atividade fibrinolítica (304 mm2) foi obtida a 1.12 g, 28 ºC e pH 8.0. O extrato bruto da fermentação foi usado para determinar as propriedades bioquímicas da enzima. Atividades proteásica e fibrinolítica foram estáveis durante 6 horas no intervalo de pH entre 6.8 - 8.4 e 5.8 - 9.2, respectivamente. Temperatura ótima para a atividade proteásica foi entre 35 - 55 °C, enquanto que para a atividade fibrinolítica foi de 45 ºC. Atividade proteásica foi inibida por íons Cu2+ e Co2+, fluoreto de fenilmetilsulfonil e pepstatina A, na qual sugere que a enzima é uma serino-protease. O extrato enzimático degradou o fibrinogênio nas subunidades Aalfa, Abeta e gama . Os resultados apresentados indicam que Streptomyces sp. DPUA 1576 produz enzimas com atividade fibrinolítica e fibrinogenolítica, enzimas com aplicações importantes na indústria farmacêutica.

First serine protease inhibitor isolated from Rhinella schneideri poison

Background Toad secretions are a source of molecules with potential biotechnological application on a wide spectrum of diseases. Toads from theRhinella family have two kinds of poisonous glands, namely granular and mucous glands. Rhinella schneideritoads produce granular secretions that comprise a great number of molecules, including serine proteases inhibitors. Serine proteases, such as trypsin, chymotrypsin and elastase, are enzymes that have a serine amino acid into its catalytic site and can be found in a large number of vertebrate species and pathogenic microorganisms. Therefore, the present work aims to purify a serine protease inhibitor from Rhinella schneiderigranular secretions.Findings This study presents the protocol used to purify a serine protease inhibitor from the Rhinella schneideri poison. The granular secretion was submitted to dialysis in order to separate the low molecular weight compounds, which were submitted to a reversed phase-fast protein liquid chromatography fractionation step in a C2C18 column. The major fractions were tested over trypsin, chymotrypsin and elastase through colorimetric assay. The inhibition tests were performed with the enzyme in absence (positive control) and presence of fractions, denatured enzyme (negative control) and the respective chromogenic substrate. Rs20 was the compound with the major inhibitory activity over chymotrypsin, inducing a delay in the formation of the chromogenic enzymatic product. The structure characterization of Rs20 was performed by high resolution electronspray ionization-mass spectrometry (HRESI-MS) and gas chromatography coupled with mass spectrometry (GC-MS). HRESI showed an intense signal suggesting the presence of bufadienolide with less than 10 ppm error. In addition, it was observed a low intense signal at m/z399 that could be lithocholic acid, a biosynthetic precursor of bufadienolide. Finally, GC-MS analysis applying NIST library identification reinforced this hypothesis.Conclusions The current study have isolated and partially characterized the function and structure of the first bufadienolide with inhibitory action over chymotrypsin.(AU)

Bothrops snake venoms and their isolated toxins, an L-amino acid oxidase and a serine protease, modulate human complement system pathways

Background Activation of the complement system plays an important role in the regulation of immune and inflammatory reactions, and contributes to inflammatory responses triggered by envenomation provoked byBothrops snakes. The present study aimed to assess whether Bothrops jararacussuand Bothrops pirajai crude venoms and their isolated toxins, namely serine protease (BjussuSP-I) and L-amino acid oxidase (BpirLAAO-I), modulate human complement system pathways.Methods Lyophilized venom and toxin samples solubilized in phosphate buffered saline were diluted in appropriate buffers to evaluate their hemolytic activity on the alternative and classical pathways of the complement system. Venom- and toxin-treated normal human serum was added to the erythrocyte suspension, and the kinetic of hemolysis was measured spectrophotometrically at 700 nm. The kinetic 96-well microassay format was used for this purpose. We determined the t ½values (time required to lyse 50 % of target erythrocytes), which were employed to calculate the percentage of inhibition of the hemolytic activity promoted by each sample concentration. To confirm complement system activation, complement-dependent human neutrophil migration was examined using the Boyden chamber model.Results At the highest concentration tested (120 μg/mL), B. jararacussu and B. pirajai crude venoms inhibited the hemolytic activity of the classical pathway (65.3 % and 72.4 %, respectively) more strongly than they suppressed the hemolytic activity of the alternative pathway (14.2 and 13.6 %, respectively). BjussuSP-I (20 μg/mL) did not affect the hemolytic activity of the classical pathway, but slightly decreased the hemolytic activity of the alternative pathway (13.4 %). BpirLAAO-I (50 μg/mL) inhibited 24.3 and 12.4 % of the hemolytic activity of the classical and alternative pathways, respectively. Normal human serum treated with B. jararacussu and B. pirajai crude venoms induced human neutrophil migration at a level similar to that induced by zymosan-activated normal human serum.Conclusion Together, the results of the kinetics of hemolysis and the neutrophil chemotaxis assay suggest that pre-activation of the complement system byB. jararacussu and B. pirajai crude venoms consumes complement components and generates the chemotactic factors C3a and C5a. The kinetic microassay described herein is useful to assess the effect of venoms and toxins on the hemolytic activity of the complement system.(AU)

Bothrops snake venoms and their isolated toxins, an L-amino acid oxidase and a serine protease, modulate human complement system pathways

Background Activation of the complement system plays an important role in the regulation of immune and inflammatory reactions, and contributes to inflammatory responses triggered by envenomation provoked byBothrops snakes. The present study aimed to assess whether Bothrops jararacussuand Bothrops pirajai crude venoms and their isolated toxins, namely serine protease (BjussuSP-I) and L-amino acid oxidase (BpirLAAO-I), modulate human complement system pathways.Methods Lyophilized venom and toxin samples solubilized in phosphate buffered saline were diluted in appropriate buffers to evaluate their hemolytic activity on the alternative and classical pathways of the complement system. Venom- and toxin-treated normal human serum was added to the erythrocyte suspension, and the kinetic of hemolysis was measured spectrophotometrically at 700 nm. The kinetic 96-well microassay format was used for this purpose. We determined the t ½values (time required to lyse 50 % of target erythrocytes), which were employed to calculate the percentage of inhibition of the hemolytic activity promoted by each sample concentration. To confirm complement system activation, complement-dependent human neutrophil migration was examined using the Boyden chamber model.Results At the highest concentration tested (120 g/mL), B. jararacussu and B. pirajai crude venoms inhibited the hemolytic activity of the classical pathway (65.3 % and 72.4 %, respectively) more strongly than they suppressed the hemolytic activity of the alternative pathway (14.2 and 13.6 %, respectively). BjussuSP-I (20 g/mL) did not affect the hemolytic activity of the classical pathway, but slightly decreased the hemolytic activity of the alternative pathway (13.4 %). BpirLAAO-I (50 g/mL) inhibited 24.3 and 12.4 % of the hemolytic activity of the classical and alternative pathways, respectively. Normal human serum treated with B. jararacussu and B. pirajai crude venoms induced human neutrophil migration at a level similar to that induced by zymosan-activated normal human serum.Conclusion Together, the results of the kinetics of hemolysis and the neutrophil chemotaxis assay suggest that pre-activation of the complement system byB. jararacussu and B. pirajai crude venoms consumes complement components and generates the chemotactic factors C3a and C5a. The kinetic microassay described herein is useful to assess the effect of venoms and toxins on the hemolytic activity of the complement system.

Extracellular proteases of Halobacillus blutaparonensis strain M9, a new moderately halophilic bacterium

Halophilic microorganisms are source of potential hydrolytic enzymes to be used in industrial and/or biotechnological processes. In the present study, we have investigated the ability of the moderately halophilic bacterium Halobacillus blutaparonensis (strain M9), a novel species described by our group, to release proteolytic enzymes. This bacterial strain abundantly proliferated in Luria-Bertani broth supplemented with 2.5% NaCl as well as secreted proteases to the extracellular environment. The production of proteases occurred in bacterial cells grown under different concentration of salt, ranging from 0.5% to 10% NaCl, in a similar way. The proteases secreted by H. blutaparonensis presented the following properties: (i) molecular masses ranging from 30 to 80 kDa, (ii) better hydrolytic activities under neutral-alkaline pH range, (iii) expression modulated according to the culture age, (iv) susceptibility to phenylmethylsulphonyl fluoride, classifying them as serine-type proteases, (v) specific cleavage over the chymotrypsin substrate, and (vi) enzymatic stability in the presence of salt (up to 20% NaCl) and organic solvents (e.g., ether, isooctane and cyclohexane). The proteases described herein are promising for industrial practices due to its haloalkaline properties.

In vivo evaluation of homeostatic effects of Echis carinatus snake venom in Iran

The venom of the family Viperidae, including the saw-scaled viper, is rich in serine proteinases and metalloproteinases, which affect the nervous system, complementary system, blood coagulation, platelet aggregation and blood pressure. One of the most prominent effects of the snake venom of Echis carinatus (Ec) is its coagulation activity, used for killing prey. Materials and methods Subfractions F1A and F1B were isolated from Ec crude venom by a combination of gel chromatography (Sephadex G-75) and ion exchange chromatography on a DEAE-Sepharose (DE-52). These subfractions were then intravenously (IV) injected into NIH male mice. Blood samples were taken before and after the administration of these subfractions. Times for prothrombin, partial thromboplastin and fibrinogen were recorded. Results and conclusions Comparison of the prothrombin time before and after F1A and F1B administrations showed that time for blood coagulation after injection is shorter than that of normal blood coagulation and also reduced coagulation time after Ec crude venom injection. This difference in coagulation time shows the intense coagulation activity of these subfractions that significantly increase the coagulation cascade rate and Causes to quick blood coagulation. The LD50 of the Ec crude venom was also determined to be 11.1 μg/mouse. Different crude venom doses were prepared with physiological serum and injected into four mice. Comparison of the prothrombin times after injection of subfractions F1A and F1B showed that the rate of mouse blood coagulation increases considerably. Comparing the partial thromboplastin times after injecting these subfractions with this normal test time showed that the activity rate of intrinsic blood coagulation system rose sharply in mice. Finally, by comparing the fibrinogen time after subfraction injections and normal test time, we can.

Isolated biomolecules of pharmacological interest in hemostasis from Cerastes cerastes venom

Biomolecules from Cerastes cerastes venom have been purified and characterized. Two phospholipases isolated from Cerastes cerastes venom share 51% of homology. CC2-PLA2 exhibits antiplatelet activity that blocks coagulation. CCSV-MPase, a non-hemorrhagic Zn2+-metalloproteinase, significantly reduced the plasmatic fibrinogen level and hydrolyzes only its Bβ chain. Serine proteinases such as RP34, afaâcytin and CC3-SPase hydrolyze the fibrinogen and are respectively α, αβ and αβ fibrinogenases. In deficient human plasma, afaâcytin replaces the missing factors VIII and IX, and activates purified human factor X into factor Xa. It releases serotonin from platelets and directly aggregates human (but not rabbit) blood platelets. RP34 proteinase also had no effect on both human and rabbit blood platelet aggregation. CC3-SPase revealed a pro-coagulant activity. However, the insolubility of the obtained clot indicates that CC3-SPase does not activate factor XIII. In addition, CC3-SPase clotting activity was carried out with human plasmas from volunteer patients deficient in clotting factors. Results showed that CC3-SPase shortens clotting time of plasma deficient in factors II and VII but with weaker clotting than normal plasma. The clotting time of plasma deficient in factor II is similar to that obtained with normal plasma; suggesting that CC3-SPase is able to replace both factors IIa and VII in the coagulation cascade and thus could be involved in the blood clotting process via an extrinsic pathway. These results imply that CC3-SPase and afaâcytin could repair hemostatic abnormalities and may replace some factors missing in pathological deficiency. Afaâcytin also exhibits α fibrinase property similar to a plasmin-like proteinase. Despite its thrombin-like characteristics, afaâcytin is not inhibited by plasmatic thrombin inhibitors. The procoagulant properties of afaâcytin might have potential clinical applications.

Eficácia do soro antibotrópico produzido no Instituto Butantan: neutralização de diferentes classes de enzimas proteolíticas do veneno total da Bothrops jararaca / Efficacy of bothropic antivenom produced by Butantan Institute: neutralization of different classes of proteolytic enzymes from the venom of Bothrops jararaca

O envenenamento ofídico representa uma questão de saúde para vários países do mundoe alguns fatores importantes devem ser levados em consideração a fim de minimizareste problema como, por exemplo, atendimento médico de qualidade e um melhor registro de acidentes. O gênero Bothrops é considerado o mais importante nos casos deenvenenamento ofídico no Brasil e, como outras serpentes, seu veneno é uma mistura complexa de componentes que agem em diferentes alvos na presa/vítima. Considerandoque as enzimas proteolíticas das classes das metalopeptidases e as serinopeptidases (cerca de 65 % da composição do veneno) são as principais toxinas do veneno da B.jararaca, as mesmas foram escolhidas no presente estudo para se determinar o nível de neutralização das suas atividades pelo soro produzido pelo Instituto Butantan, o qual éamplamente utilizado no Brasil. Para isso dois substratos FRETs foram selecionados, a partir de uma biblioteca de peptídeos, que se comportaram como alvos seletivos para as serino- e metalopeptidases. Desta maneira, observamos que o soro é ineficiente no bloqueio da atividade de duas serinopeptidases e, este fato nos levou à busca dos motivos pelos quais o soro antibotrópico comercial estaria apresentando esta falha. Assim, estas duas serinopeptidases ainda inéditas no veneno de Bothrops jararaca e não neutralizadas pelo soro comercial foram purificadas e identificadas e verificamos que a razão na falha do soro comercial em bloquear estas atividades é ausência de anticorpos específicos contra estas enzimas já que as mesmas não eram reconhecidas pelo soro no ensaio de western blot. Assim, nossos resultados indicam uma possível falha na composição do soro antibotrópico, portanto fomos levados a estudar mais profundamente o papel destas serinopeptidases e buscamos novos substratos para estasenzimas...

Obtenção de peptídeos bioativos (criptídeos) pela ação da tripsina e serinoproteases do veneno de Bothrops jararaca sobre substratos endógenos / Obtention of bioactive peptives (cryprides) by the action of trypsin and serine proteases from the venom of Bothrops jararaca on endogenous substrates

As serinoproteases e metaloproteases são as principais enzimas do veneno de Bothrops jararaca, elas agem sobre as proteínas dos tecidos das vítimas ou presas, e como resultado de suas ações diretas, essas proteases podem gerar peptídeos com ações específicas em células ou ainda afetar mecanismos fisiológicos. As fontes mais comuns de peptídeos bioativos são as proteínas precursoras naturais. No entanto, estudos recentes têm mostrado que existem outras fontes de peptídeos bioativos, as cripteínas, que fazem parte de uma nova classe de proteínas que não são consideradas precursoras, mas sob certas condições, originam peptídeos bioativos, assim eles são denominados criptídeos. Os criptídeos podem provocar efeitos relevantes na questão do envenenamento, causando efeitos secundários ou indiretos. Neste trabalho, esses criptídeos gerados pela ação das serinoproteases do veneno e pela ação da tripsina sobre substratos endógenos, foram isolados, e em seguida foram caracterizados bioquimicamente e biologicamente de acordo com suas ações em células. As serinoproteases do veneno de B. jararaca foram separadas do veneno total utilizando CLAE com uma coluna de exclusão molecular, estas serinoproteases foram então incubadas com o substrato mioglobina. Como também foi utilizado a tripsina, foram escolhidos os seguintes substratos, mioglobina, hemoglobina, immunoglobulina G e colágeno, que foram incubados com a tripsina.Os criptídeos gerados foram separados por fracionamento por CLAE e as frações foram testadas em culturas de células para observar efeitos citotóxicos ou proliferativos. As frações ativas foram repurificadas para obter criptídeos puros. Com a atividade desses criptídeos confirmada, estes foram sequenciados e sintetizados. A ação da tripsina sobre a mioglobina gerou criptídeos (ALELFR, TGHPETLEK, GLSDGEWQQVLNVWGK) que apresentaram atividade proliferativa em células do tipo fibroblastos e endoteliais. Utilizando um programa de bioinformática, Cn3D, observou-se...