RESUMO
Insects are of great interest as novel sources of alternative proteins and biologically active compounds, primarily anticancer agents. Protein-rich insect larval hemolymph is a prospective candidate for pharmaceutical and food industry-related research. In this study, selected biochemical properties and cell toxicity of larval hemolymph from two mealworm species, Tenebrio molitor and Zophobas morio, were analyzed. Total proteins and carbohydrates, antioxidant capacity, and the level of lipid peroxidation were determined. Human cancer (U-87) and normometabolic (MRC-5) cells were treated with different concentrations of larval hemolymph proteins, and the effects on cell viability were assayed 24, 48, and 72 h after treatments. Z. morio hemolymph was shown to be richer in total proteins, showing a higher antioxidant capacity and lipid peroxidation level than T. molitor hemolymph, which was richer in total carbohydrates. Cytotoxicity assays showed that T. molitor and Z. morio hemolymphs differently affect the viability of U-87 and MRC-5 cells in cell type-, dose-, and time-dependent manners. Hemolymph from both species was more cytotoxic to U-87 cells than to MRC-5 cells, which was particularly prominent after 48 h. Additionally, a more potent cytotoxic effect of Z. morio hemolymph was observed on both cell lines, likely due to its higher antioxidant capacity, compared to T. molitor hemolymph.
Assuntos
Antioxidantes , Hemolinfa , Larva , Tenebrio , Animais , Hemolinfa/metabolismo , Tenebrio/efeitos dos fármacos , Larva/efeitos dos fármacos , Humanos , Antioxidantes/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Antineoplásicos/farmacologia , Proteínas de Insetos/metabolismoRESUMO
Strain improvement via chemical mutagen could impart traits with better enzyme production or improved characteristics. The present study sought to investigate the physicochemical properties of pullulanase produced from the wild Bacillus sp and the mutant. The pullulanases produced from the wild and the mutant Bacillus sp. (obtained via induction with ethyl methyl sulfonate) were purified in a-three step purification procedure and were also characterized. The wild and mutant pullulanases, which have molecular masses of 40 and 43.23 kDa, showed yields of 2.3% with 6.0-fold purification and 2.0% with 5.0-fold purification, respectively, and were most active at 50 and 40 °C and pH 7 and 8, respectively. The highest stability of the wild and mutant was between 40 and 50 °C after 1 h, although the mutant retained greater enzymatic activity between pH 6 and 9 than the wild. The mutant had a decreased Km of 0.03 mM as opposed to the wild type of 1.6 mM. In comparison to the wild, the mutant demonstrated a better capacity for tolerating metal ions and chelating agents. These exceptional characteristics of the mutant pullulanase may have been caused by a single mutation, which could improve its utility in industrial and commercial applications.
Assuntos
Bacillus , Bacillus/metabolismo , Glicosídeo Hidrolases/metabolismo , Concentração de Íons de Hidrogênio , Estabilidade Enzimática , TemperaturaRESUMO
Euphorbiaceae, also known as the spurge family, is a large group of flowering plants. Despite being tropical natives, they are now widespread. Due to its medicinal and commercial importance, this family of plants attracted a lot of attention in the scientific community. The distinctive characteristic of the family is production of milky latex, which is a rich source of several lectins, the proteins that bind carbohydrates. Although their function is unclear, they are believed to defend plants against damaging phytopathogenic microorganisms, insects, and predatory animals. Additionally, they serve as crucial metabolic regulators under a variety of stressors. Detection, separation, purification, and characterization of lectins from the Euphorbiaceae family - mostly from the latex of plants - began over 40 years ago. This effort produced over 35 original research papers that were published. However, no systematic review that compiles these published data has been presented yet. This review summarizes and describes several procedures and protocols employed for extraction and purification of lectins belonging to this family. Physicochemical properties and biological activities of the lectins, along with their medicinal and pharmacological properties, have also been analyzed. Additionally, using examples of ricin and ricin agglutinin, we have structurally analyzed characteristics of the lectin known as Ribosome Inactivating Protein Type II (RIP-Type II) that belongs to this family. We anticipate that this review article will offer a useful compendium of information on this important family of lectins, show the scientists involved in lectin research the gaps in our knowledge, and offer insights for future research.
Assuntos
Euphorbiaceae , Ricina , Animais , Ricina/química , Lectinas de Plantas/farmacologia , Látex/química , PlantasRESUMO
Acid phosphatases (EC 3.1.3.2) are the enzymes that catalyse transphosphorylation reactions and promotes the hydrolysis of numerous orthophosphate esters in acidic media, as a crucial element for the metabolism of phosphate in tissues. Inorganic phosphate (Pi) utilisation and scavenging, as well as the turnover of Pi-rich sources found in plant vacuoles, are major processes in which intracellular and secretory acid phosphatases function. Therefore, a thorough understanding of these enzymes' structural characteristics, specificity, and physiochemical properties is required to comprehend the function of acid phosphatases in plant energy metabolism. Furthermore, acid phosphatases are gaining increasing importance in industrial biotechnology due to their involvement in transphosphorylation processes and their ability to reduce phosphate levels in food products. Hence, this review aims to provide a comprehensive overview of the purification methods employed for isolating acid phosphatases from diverse plant sources, as well as their structural and functional properties. Additionally, the review explores the potential applications of these enzymes in various fields.
Assuntos
Fosfatase Ácida , Plantas , Fosfatase Ácida/química , Fosfatase Ácida/metabolismo , Hidrólise , FosfatosRESUMO
Heat stress is one of the most stressful events in livestock life, negatively impacting animal health, productivity, and product quality. Moreover, the negative impact of heat stress on animal product quality has recently attracted increasing public awareness and concern. The purpose of this review is to discuss the effects of heat stress on the quality and the physicochemical component of meat in ruminants, pigs, rabbits, and poultry. Based on PRISMA guidelines, research articles were identified, screened, and summarized based on inclusion criteria for heat stress on meat safety and quality. Data were obtained from the Web of Science. Many studies reported the increased incidences of heat stress on animal welfare and meat quality. Although heat stress impacts can be variable depending on the severity and duration, the exposure of animals to heat stress (HS) can affect meat quality. Recent studies have shown that HS not only causes physiological and metabolic disturbances in living animals but also alters the rate and extent of glycolysis in postmortem muscles, resulting in changes in pH values that affect carcasses and meat. It has been shown to have a plausible effect on quality and antioxidant activity. Acute heat stress just before slaughter stimulates muscle glycogenolysis and can result in pale, tender, and exudative (PSE) meat characterized by low water-holding capacity (WHC). The enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) act by scavenging both intracellular and extracellular superoxide radicals and preventing the lipid peroxidation of the plasma membrane. Therefore, understanding and controlling environmental conditions is crucial to successful animal production and product safety. The objective of this review was to investigate the effects of HS on meat quality and antioxidant status.
Assuntos
Antioxidantes , Galinhas , Animais , Coelhos , Suínos , Antioxidantes/metabolismo , Galinhas/metabolismo , Carne/análise , Resposta ao Choque Térmico , Aves DomésticasRESUMO
Chromium (Cr) can exist in several oxidation states, but the two most stable forms-Cr(III) and Cr(VI)-have completely different biochemical characteristics. The aim of the present study was to evaluate how soil contamination with Cr(III) and Cr(VI) in the presence of Na2EDTA affects Avena sativa L. biomass; assess the remediation capacity of Avena sativa L. based on its tolerance index, translocation factor, and chromium accumulation; and investigate how these chromium species affect the soil enzyme activity and physicochemical properties of soil. This study consisted of a pot experiment divided into two groups: non-amended and amended with Na2EDTA. The Cr(III)- and Cr(VI)-contaminated soil samples were prepared in doses of 0, 5, 10, 20, and 40 mg Cr kg-1 d.m. soil. The negative effect of chromium manifested as a decreased biomass of Avena sativa L. (aboveground parts and roots). Cr(VI) proved to be more toxic than Cr(III). The tolerance indices (TI) showed that Avena sativa L. tolerates Cr(III) contamination better than Cr(VI) contamination. The translocation values for Cr(III) were much lower than for Cr(VI). Avena sativa L. proved to be of little use for the phytoextraction of chromium from soil. Dehydrogenases were the enzymes which were the most sensitive to soil contamination with Cr(III) and Cr(VI). Conversely, the catalase level was observed to be the least sensitive. Na2EDTA exacerbated the negative effects of Cr(III) and Cr(VI) on the growth and development of Avena sativa L. and soil enzyme activity.
Assuntos
Avena , Poluentes do Solo , Solo/química , Ácido Edético , Poluentes do Solo/análise , Cromo/químicaRESUMO
Many researchers have found fungi as a reliable source of lipase due to the versatility of their properties, ease of mass production, thermal stability, pH stability, broad substrate specificity, retained activity in organic solvents, and their low-cost extraction procedure. This review paper presents an overview about the main aspects of fungal lipases screened from several types of strains as well as their use as biocatalysts. Additionally, some biochemical properties will be reported. As commonly known, lipases can be produced from animals, plants, and microorganisms. Compared to other lipases, those obtained from fungi have been found to be more productive, a fact that encouraged the massive production of most fungal lipases due to their considerable commercial importance during the past few years. This paper is concerned about some of the major characteristics that made fungal lipases desirable products in the industrial fields. Due to the enantioselective properties of fungal lipases and their ability to remain active under extreme temperature, pH, and organic solvents, enzymes are capable to synthesize esters as well as to catalyze a variety of chemical reactions that include esterification, transesterification, acidolysis and aminolysis in aqueous and nonaqueous media. Furthermore, lipases are considered to have a commercial importance for biotechnological application fields, which makes them increasingly popular in food, detergent, cosmetic, organic synthesis, and pharmaceutical domains. The biotechnological potential of lipases has made the latter a coveted choice in industries for the present and future as biocatalysts. In addition, a classification of these fungal enzymes is also highlighted in this review. Moreover, the impact of an immobilization strategy of these fungal strains to achieve higher yields and to improve their production is discussed. Finally, fungal enzymes have played a crucial role from ancient times to today in different fields using several types of biological systems, which gives them a great interest for the production of these enzymes in large amounts with low cost and easy viability to enlarge their use in many industries. Likewise, some future perspectives on lipase production will also be discussed by focusing on special cases on lipase engineering.
Assuntos
Biotecnologia , Lipase , Animais , Lipase/química , Biotecnologia/métodos , Esterificação , Catálise , SolventesRESUMO
Some cephalopods (squids, octopuses, and cuttlefishes) produce dynamic structural colors, for camouflage or communication. The key to this remarkable capability is one group of specialized cells called iridocytes, which contain aligned membrane-enclosed platelets of high-reflective reflectins and work as intracellular Bragg reflectors. These reflectins have unusual amino acid compositions and sequential properties, which endows them with functional characteristics: an extremely high reflective index among natural proteins and the ability to answer various environmental stimuli. Based on their unique material composition and responsive self-organization properties, the material community has developed an impressive array of reflectin- or iridocyte-inspired optical systems with distinct tunable reflectance according to a series of internal and external factors. More recently, scientists have made creative attempts to engineer mammalian cells to explore the function potentials of reflectin proteins as well as their working mechanism in the cellular environment. Progress in wide scientific areas (biophysics, genomics, gene editing, etc.) brings in new opportunities to better understand reflectins and new approaches to fully utilize them. The work introduced the composition features, biochemical properties, the latest developments, future considerations of reflectins, and their inspiration applications to give newcomers a comprehensive understanding and mutually exchanged knowledge from different communities (e.g., biology and material).
Assuntos
Decapodiformes , Proteínas , Animais , Proteínas/química , Decapodiformes/química , Aminoácidos , Mamíferos/metabolismoRESUMO
Dextran, a renewable hydrophilic polysaccharide, is nontoxic, highly stable but intrinsically biodegradable. The α-1, 6 glycosidic bonds in dextran are attacked by dextranase (E.C. 3.2.1.11) which is an inducible enzyme. Dextranase finds many applications such as, in sugar industry, in the production of human plasma substitutes, and for the treatment and prevention of dental plaque. Currently, dextranases are obtained from terrestrial fungi which have longer duration for production but not very tolerant to environmental conditions and have safety concerns. Marine bacteria have been proposed as an alternative source of these enzymes and can provide prospects to overcome these issues. Indeed, marine bacterial dextranases are reportedly more effective and suitable for dental caries prevention and treatment. Here, we focused on properties of dextran, properties of dextran-hydrolyzing enzymes, particularly from marine sources and the biochemical features of these enzymes. Lastly the potential use of these marine bacterial dextranase to remove dental plaque has been discussed. The review covers dextranase-producing bacteria isolated from shrimp, fish, algae, sea slit, and sea water, as well as from macro- and micro fungi and other microorganisms. It is common knowledge that dextranase is used in the sugar industry; produced as a result of hydrolysis by dextranase and have prebiotic properties which influence the consistency and texture of food products. In medicine, dextranases are used to make blood substitutes. In addition, dextranase is used to produce low molecular weight dextran and cytotoxic dextran. Furthermore, dextranase is used to enhance antibiotic activity in endocarditis. It has been established that dextranase from marine bacteria is the most preferable for removing plaque, as it has a high enzymatic activity. This study lays the groundwork for the future design and development of different oral care products, based on enzymes derived from marine bacteria.
Assuntos
Dextranase , Animais , Bactérias/enzimologia , Cárie Dentária , Placa Dentária , Dextranase/química , Dextranase/uso terapêutico , Dextranos/química , Fungos , Humanos , AçúcaresRESUMO
BACKGROUND: Alanine decarboxylase (AlaDC), specifically present in tea plants, is crucial for theanine biosynthesis. Serine decarboxylase (SDC), found in many plants, is a protein most closely related to AlaDC. To investigate whether the new gene AlaDC originate from gene SDC and to determine the biochemical properties of the two proteins from Camellia sinensis, the sequences of CsAlaDC and CsSDC were analyzed and the two proteins were over-expressed, purified, and characterized. RESULTS: The results showed that exon-intron structures of AlaDC and SDC were quite similar and the protein sequences, encoded by the two genes, shared a high similarity of 85.1%, revealing that new gene AlaDC originated from SDC by gene duplication. CsAlaDC and CsSDC catalyzed the decarboxylation of alanine and serine, respectively. CsAlaDC and CsSDC exhibited the optimal activities at 45 °C (pH 8.0) and 40 °C (pH 7.0), respectively. CsAlaDC was stable under 30 °C (pH 7.0) and CsSDC was stable under 40 °C (pH 6.0-8.0). The activities of the two enzymes were greatly enhanced by the presence of pyridoxal-5'-phosphate. The specific activity of CsSDC (30,488 IU/mg) was 8.8-fold higher than that of CsAlaDC (3467 IU/mg). CONCLUSIONS: Comparing to CsAlaDC, its ancestral enzyme CsSDC exhibited a higher specific activity and a better thermal and pH stability, indicating that CsSDC acquired the optimized function after a longer evolutionary period. The biochemical properties of CsAlaDC might offer reference for theanine industrial production.
Assuntos
Alanina Desidrogenase/genética , Alanina Desidrogenase/metabolismo , Camellia sinensis/enzimologia , Camellia sinensis/genética , Serina/metabolismo , Alanina/metabolismo , Alanina Desidrogenase/química , Carboxiliases/genética , Escherichia coli/genética , Glutamatos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Recombinantes , CháRESUMO
Gonorrhoea, caused by Neisseria gonorrhoeae, is a major global public health concern. Homoserine dehydrogenase (HSD), a key enzyme in the aspartate pathway, is a promising metabolic target against pathogenic infections. In this study, a monofunctional HSD from N. gonorrhoeae (NgHSD) was overexpressed in Escherichia coli and purified to >95% homogeneity for biochemical characterization. Unlike the classic dimeric structure, the purified recombinant NgHSD exists as a tetramer in solution. We determined the enzymatic activity of recombinant NgHSD for l-homoserine oxidation, which revealed that this enzyme was NAD+ dependent, with an approximate 479-fold (kcat/Km) preference for NAD+ over NADP+, and that optimal activity for l-homoserine oxidation occurred at pH 10.5 and 40 °C. At 800 mM, neither NaCl nor KCl increased the activity of NgHSD, in contrast to the behavior of several reported NAD+-independent homologs. Moreover, threonine did not markedly inhibit the oxidation activity of NgHSD. To gain insight into the cofactor specificity, site-directed mutagenesis was used to alter coenzyme specificity. The double mutant L45R/S46R, showing the highest affinity for NADP+, caused a shift in coenzyme preference from NAD+ to NADP+ by a factor of ~974, with a catalytic efficiency comparable with naturally occurring NAD+-independent homologs. Collectively, our results should allow the exploration of drugs targeting NgHSD to treat gonococcal infections and contribute to the prediction of the coenzyme specificity of novel HSDs.
Assuntos
Coenzimas , Homosserina Desidrogenase , NAD , Neisseria gonorrhoeae , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Coenzimas/química , Coenzimas/metabolismo , Escherichia coli/genética , Gonorreia/microbiologia , Homosserina Desidrogenase/genética , Homosserina Desidrogenase/metabolismo , Humanos , Mutagênese Sítio-Dirigida , NAD/química , NAD/metabolismo , NADP/química , NADP/metabolismo , Neisseria gonorrhoeae/enzimologia , Neisseria gonorrhoeae/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato/genéticaRESUMO
Homoserine dehydrogenase (HSD), encoded by the hom gene, is a key enzyme in the aspartate pathway, which reversibly catalyzes the conversion of l-aspartate ß-semialdehyde to l-homoserine (l-Hse), using either NAD(H) or NADP(H) as a coenzyme. In this work, we presented the first characterization of the HSD from the symbiotic Polynucleobacter necessaries subsp. necessarius (PnHSD) produced in Escherichia coli. Sequence analysis showed that PnHSD is an ACT domain-containing monofunctional HSD with 436 amnio acid residues. SDS-PAGE and Western blot demonstrated that PnHSD could be overexpressed in E. coli BL21(DE3) cell as a soluble form by using SUMO fusion technique. It could be purified to apparent homogeneity for biochemical characterization. Size-exclusion chromatography revealed that the purified PnHSD has a native molecular mass of â¼160 kDa, indicating a homotetrameric structure. The oxidation activity of PnHSD was studied in this work. Kinetic analysis revealed that PnHSD displayed an up to 1460-fold preference for NAD+ over NADP+, in contrast to its homologs. The purified PnHSD displayed maximal activity at 35 °C and pH 11. Similar to its NAD+-dependent homolog, neither NaCl and KCl activation nor L-Thr inhibition on the enzymatic activity of PnHSD was observed. These results will contribute to a better understanding of the coenzyme specificity of the HSD family and the aspartate pathway of P. necessarius.
Assuntos
Ácido Aspártico/biossíntese , Proteínas de Bactérias/genética , Burkholderiaceae/enzimologia , Homosserina Desidrogenase/genética , NAD/metabolismo , Proteínas Recombinantes de Fusão/genética , Sequência de Aminoácidos , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/isolamento & purificação , Burkholderiaceae/química , Burkholderiaceae/genética , Cromatografia em Gel , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Euplotes/microbiologia , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Homosserina/metabolismo , Homosserina Desidrogenase/biossíntese , Homosserina Desidrogenase/isolamento & purificação , Cinética , Peso Molecular , NADP/metabolismo , Multimerização Proteica , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/isolamento & purificação , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Simbiose/fisiologiaRESUMO
SARS-CoV-2 is mutating and creating divergent variants across the world. An in-depth investigation of the amino acid substitutions in the genomic signature of SARS-CoV-2 proteins is highly essential for understanding its host adaptation and infection biology. A total of 9587 SARS-CoV-2 structural protein sequences collected from 49 different countries are used to characterize protein-wise variants, substitution patterns (type and location), and major substitution changes. The majority of the substitutions are distinct, mostly in a particular location, and lead to a change in an amino acid's biochemical properties. In terms of mutational changes, envelope (E) and membrane (M) proteins are relatively more stable than nucleocapsid (N) and spike (S) proteins. Several co-occurrence substitutions are observed, particularly in S and N proteins. Substitution specific to active sub-domains reveals that heptapeptide repeat, fusion peptides, transmembrane in S protein, and N-terminal and C-terminal domains in the N protein are remarkably mutated. We also observe a few deleterious mutations in the above domains. The overall study on non-synonymous mutation in structural proteins of SARS-CoV-2 at the start of the pandemic indicates a diversity amongst virus sequences.
Assuntos
SARS-CoV-2/química , Proteínas Estruturais Virais/química , Proteínas Estruturais Virais/genética , Substituição de Aminoácidos , Aminoácidos/química , Proteínas do Envelope de Coronavírus/química , Proteínas do Envelope de Coronavírus/genética , Proteínas do Nucleocapsídeo de Coronavírus/química , Proteínas do Nucleocapsídeo de Coronavírus/genética , Humanos , Mutação , Taxa de Mutação , Fosfoproteínas/química , Fosfoproteínas/genética , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Proteínas da Matriz Viral/química , Proteínas da Matriz Viral/genéticaRESUMO
Alginate, the most abundant polysaccharides of brown algae, consists of various proportions of uronic acid epimers α-L-guluronic acid (G) and ß-D-mannuronic acid (M). Alginate oligosaccharides (AOs), the degradation products of alginates, exhibit excellent bioactivities and a great potential for broad applications in pharmaceutical fields. Alginate lyases can degrade alginate to functional AOs with unsaturated bonds or monosaccharides, which can facilitate the biorefinery of brown algae. On account of the increasing applications of AOs and biorefinery of brown algae, there is a scientific need to explore the important aspects of alginate lyase, such as catalytic mechanism, structure, and property. This review covers fundamental aspects and recent developments in basic information, structural characteristics, the structure-substrate specificity or catalytic efficiency relationship, property, molecular modification, and applications. To meet the needs of biorefinery systems of a broad array of biochemical products, alginate lyases with special properties, such as salt-activated, wide pH adaptation range, and cold adaptation are outlined. Withal, various challenges in alginate lyase research are traced out, and future directions, specifically on the molecular biology part of alginate lyases, are delineated to further widen the horizon of these exceptional alginate lyases.
Assuntos
Alginatos/farmacologia , Phaeophyceae , Polissacarídeos/farmacologia , Alginatos/química , Animais , Organismos Aquáticos , Humanos , Polissacarídeos/química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
L-asparaginase (L-ASNase) is a biotechnologically relevant enzyme for the pharmaceutical, biosensor and food industries. Efforts to discover new promising L-ASNases for different fields of biotechnology have turned this group of enzymes into a growing family with amazing diversity. Here, we report that thermophile Melioribacter roseus from Ignavibacteriae of the Bacteroidetes/Chlorobi group possesses two L-ASNases-bacterial type II (MrAII) and plant-type (MrAIII). The current study is focused on a novel L-ASNase MrAII that was expressed in Escherichia coli, purified and characterized. The enzyme is optimally active at 70 °C and pH 9.3, with a high L-asparaginase activity of 1530 U/mg and L-glutaminase activity ~19% of the activity compared with L-asparagine. The kinetic parameters KM and Vmax for the enzyme were 1.4 mM and 5573 µM/min, respectively. The change in MrAII activity was not significant in the presence of 10 mM Ni2+, Mg2+ or EDTA, but increased with the addition of Cu2+ and Ca2+ by 56% and 77%, respectively, and was completely inhibited by Zn2+, Fe3+ or urea solutions 2-8 M. MrAII displays differential cytotoxic activity: cancer cell lines K562, Jurkat, LnCap, and SCOV-3 were more sensitive to MrAII treatment, compared with normal cells. MrAII represents the first described enzyme of a large group of uncharacterized counterparts from the Chlorobi-Ignavibacteriae-Bacteroidetes clade.
Assuntos
Asparaginase/metabolismo , Bactérias/enzimologia , Sequência de Aminoácidos , Asparaginase/química , Asparaginase/genética , Asparaginase/isolamento & purificação , Asparagina/metabolismo , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Estabilidade Enzimática , Evolução Molecular , Glutaminase/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Cinética , Alinhamento de SequênciaRESUMO
L-asparaginase (L-ASNase) is a vital enzyme with a broad range of applications in medicine and food industry. Drawbacks of current commercial L-ASNases stimulate the search for better-producing sources of the enzyme, and extremophiles are especially attractive in this view. In this study, a novel L-asparaginase originating from the hyperthermophilic archaeon Thermococcus sibiricus (TsA) was expressed in Escherichia coli, purified and characterized. The enzyme is optimally active at 90 °C and pH 9.0 with a specific activity of 2164 U/mg towards L-asparagine. Kinetic parameters KM and Vmax for the enzyme are 2.8 mM and 1200 µM/min, respectively. TsA is stable in urea solutions 0-6 M and displays no significant changes of the activity in the presence of metal ions Ni2+, Cu2+, Mg2+, Zn2+ and Ca2+ and EDTA added in concentrations 1 and 10 mmol/L except for Fe3+. The enzyme retains 86% of its initial activity after 20 min incubation at 90 °C, which should be enough to reduce acrylamide formation in foods processed at elevated temperatures. TsA displays strong cytotoxic activity toward cancer cell lines K562, A549 and Sk-Br-3, while normal human fibroblasts WI-38 are almost unsensitive to it. The enzyme seems to be a promising candidate for further investigation and biotechnology application.
Assuntos
Archaea/enzimologia , Asparaginase/isolamento & purificação , Biotecnologia/tendências , Thermococcus/enzimologia , Sequência de Aminoácidos/genética , Antineoplásicos/química , Antineoplásicos/farmacologia , Asparaginase/química , Asparaginase/genética , Asparagina/metabolismo , Estabilidade Enzimática/genética , Escherichia coli/efeitos dos fármacos , Cinética , Especificidade por Substrato/genéticaRESUMO
The human enzyme D-3-phosphoglycerate dehydrogenase (hPHGDH) catalyzes the reversible dehydrogenation of 3-phosphoglycerate (3PG) into 3-phosphohydroxypyruvate (PHP) using the NAD+/NADH redox cofactor, the first step in the phosphorylated pathway producing L-serine. We focused on the full-length enzyme that was produced in fairly large amounts in E. coli cells; the effect of pH, temperature and ligands on hPHGDH activity was studied. The forward reaction was investigated on 3PG and alternative carboxylic acids by employing two coupled assays, both removing the product PHP; 3PG was by far the best substrate in the forward direction. Both PHP and α-ketoglutarate were efficiently reduced by hPHGDH and NADH in the reverse direction, indicating substrate competition under physiological conditions. Notably, neither PHP nor L-serine inhibited hPHGDH, nor did glycine and D-serine, the coagonists of NMDA receptors related to L-serine metabolism. The investigation of NADH and phosphate binding highlights the presence in solution of different conformations and/or oligomeric states of the enzyme. Elucidating the biochemical properties of hPHGDH will enable the identification of novel approaches to modulate L-serine levels and thus to reduce cancer progression and treat neurological disorders.
Assuntos
Fosfoglicerato Desidrogenase/metabolismo , Ácidos Carboxílicos/metabolismo , Escherichia coli/metabolismo , Glicina/metabolismo , Humanos , Cinética , NAD/metabolismo , Fosfoglicerato Desidrogenase/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Serina/metabolismoRESUMO
Proteolytic enzymes hold a pivotal position in numerous industrial processes where hydrolysis of protein molecules is required under precise conditions. The emerging trend of biotechnological applications in recent years has witnessed a renewed interest in alkaline serine proteases extending their utility in detergent, leather, textile, food and pharmaceutical industries. A variety of microorganisms have been reported to produce alkaline serine proteases on a large scale, however, extensive research to find an alkaline serine protease with desirable characteristics such as significant catalytic efficiency, expanded stability and broad substrate specificity is still ongoing. Although submerged fermentation dominates the commercial enzyme production, recent reports have emphasized on solid state fermentation technology which can reduce major cost associated with the enzyme production. In the present review, recent research on alkaline serine proteases along with their novel properties and production using solid state fermentation have been discussed.
Assuntos
Proteínas de Bactérias/metabolismo , Biotecnologia , Serina Endopeptidases/metabolismo , Detergentes , Endopeptidases/metabolismo , Fermentação , Indústria Alimentícia , Concentração de Íons de Hidrogênio , Hidrólise , Serina/metabolismo , Serina Proteases/metabolismo , Especificidade por Substrato , TemperaturaRESUMO
Marine-derived enzymes have recently gained attention particularly for industrial applications. Cellulose-degrading enzymes are among leading biocatalysts with potential utility in biorefineries. This review presents an account of the cellulase production by marine sources from microorganisms including bacteria, yeasts, and molds to marine invertebrates such as protist, rotifer, mollusks, arthropods, and echinoderms. Cellulose-degrading ability of marine invertebrates is attributed to the production of endogenous cellulases and activities by the symbionts. Specialized environments in marine including estuaries and mangroves are rich in lignocellulosic biomass and hence provide a feeding ground for cellulose digesters. Since cellulosic biomass is considered chemical and energy feedstock, therefore, cellulases with the ability to work under extreme environment are much needed to fulfill the demand of modern biotechnological industries. The review also discusses physicochemical parameters of marine-derived cellulases. Key Points: ⢠Cellulolytic ability is widely distributed amongst marine organisms, yet very few have been studied for their biotechnological potential ⢠Cellulase from marine organisms has been demonstrated as a successful agent in degradation of seaweed processing waste to low molecular fragments ⢠Marine derived cellulases can find their application in green processes ⢠Cellulases from marine sources exhibit high specific activity, thermostability, and other important biochemical properties and hence can contend well with the enzymes from terrestrial sources.
Assuntos
Organismos Aquáticos/enzimologia , Celulases/metabolismo , Celulose/metabolismo , Animais , Bactérias/enzimologia , Biocatálise , Biocombustíveis , Biomassa , Biotecnologia/métodos , Fungos/enzimologia , Invertebrados/enzimologiaRESUMO
Copper (Cu) mining has to address a critical environmental issue related to the disposal of heavy metals and metalloids (HMs). Due to their deleterious effects on living organisms, Cu and arsenic (As) have gained global attention, and thus their monitoring in the environment is an important task. The aims of this study were: 1) to evaluate the alteration of soil enzyme activities (EAs) and soil microbial functional diversity with Cu/As contamination, and 2) to select the most reliable biochemical indicators of Cu/As contamination. A twelve-week soil experiment was performed with four increasing levels of Cu, As, and Cu/As from 150/15 to 1000/100 mg Cu/As kg-1. Soil enzyme activities and soil community-level physiological profile (CLPP) using MicroResp™ were measured during the experiment. Results showed reduced EAs over time with increasing Cu and Cu/As levels. The most Cu-sensitive EAs were dehydrogenase, acid phosphatase, and arylsulfatase, while arginine ammonification might be related to the resilience of soil microbial communities due to its increased activity in the last experimental times. There was no consistent response to As contamination with reduced individual EAs at specific sampling times, being urease the only EA negatively affected by As. MicroResp™ showed reduced carbon (C) substrate utilization with increasing Cu levels indicating a community shift in C acquisition. These results support the use of specific EAs to assess the environmental impact of specific HMs, being also the first assessment of EAs and the use of CLPP (MicroResp™) to study the environmental impact in Cu/As contaminated soils.