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1.
Electrophoresis ; 41(13-14): 1137-1151, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32469436

RESUMO

The material properties of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its proteins are discussed. We review the viral structure, size, rigidity, lipophilicity, isoelectric point, buoyant density and centrifugation conditions, stability against pH, temperature, UV light, gamma radiation, and susceptibility to various chemical agents including solvents and detergents. Possible inactivation, downstream, and formulation conditions are given including suitable buffers and some first ideas for quality-control methods. This information supports vaccine development and discussion with competent authorities during vaccine approval and is certainly related to drug-targeting strategies and hygienics. Several instructive tables are given, including the pI and grand average of hydropathicity (GRAVY) of SARS-CoV-1 and -2 proteins in comparison. SARS-CoV-1 and SARS-CoV-2 are similar in many regards, so information can often be derived. Both are unusually stable, but sensitive at their lipophilic membranes. However, since seemingly small differences can have strong effects, for example, on immunologically relevant epitope settings, unevaluated knowledge transfer from SARS-CoV-1 to SARS-CoV-2 cannot be advised. Published knowledge regarding downstream processes, formulations and quality assuring methods is, as yet, limited. However, standard approaches employed for other viruses and vaccines seem to be feasible including virus inactivation, centrifugation conditions, and the use of adjuvants.


Assuntos
Betacoronavirus/química , Proteínas Virais/química , Vacinas Virais/farmacologia , Animais , Betacoronavirus/efeitos dos fármacos , Betacoronavirus/efeitos da radiação , Desinfetantes/farmacologia , Eletroforese , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Raios Ultravioleta , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/farmacologia , Vacinas Virais/imunologia , Inativação de Vírus/efeitos da radiação
2.
J Biosci Bioeng ; 129(1): 59-66, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31324383

RESUMO

In this study, we used the commercial soybean protein hydrolysate Hinute-DC6 as a novel starting material from which to purify and identify multifunctional cationic peptides. After fractionation, Hinute-DC6 was separated into 20 fractions with varying isoelectric points (pI) by ampholyte-free isoelectric focusing (autofocusing). Subsequently, we purified and identified the cationic peptides from fractions 19 and 20, which had pI values greater than 12, using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectrometry. Of the 83 cationic peptides identified, 14 had high pI values and net charges greater than +2, and were chemically synthesized and assayed for various bioactivities, including hemolytic, antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. None of the 14 cationic peptides tested exhibited hemolytic activity toward mammalian red blood cells at concentrations up to 1000 µM. Five of the cationic peptides exhibited antimicrobial activities against at least one of four human-pathogenic microorganisms tested. In addition, in chromogenic LPS-neutralizing assays using Limulus amebocyte lysates, the 50% effective concentrations of these 14 peptides were between 0.069 and 5.2 µM. Tube-formation assays in human umbilical vein endothelial cells showed that each of the 14 cationic peptides exhibited significant angiogenic activities at 10 µM, with values similar to those of the positive control LL-37. Our results demonstrate that the 14 identified cationic peptides have multiple functions with negligible hemolytic activity. These data indicate that the cationic peptides isolated from Hinute-DC6 and fractions containing these cationic peptides have the potential to be used as multifunctional ingredients for healthcare applications.


Assuntos
Peptídeos/química , Proteínas de Soja/química , Indutores da Angiogênese/química , Indutores da Angiogênese/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Hemólise , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Hidrólise , Ponto Isoelétrico , Peptídeos/farmacologia , Hidrolisados de Proteína/química , Soja/química
3.
Biosci Biotechnol Biochem ; 84(2): 238-246, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31625450

RESUMO

The Cel genes from Bacillus licheniformis MSB03 were cloned and expressed to investigate binding ability on clay minerals and sea sand at pH ranging 3 to 9. FTIR analysis has been done to characterize bound enzymes on clay minerals. Subsequent, surveying of NCBI database for extracellular enzymes of soil bacteria was carried out. Among the five cloned Cel enzymes assayed for binding to clay minerals, only Cel5H enzyme had the binding ability. Enzyme Cel5H exhibited highest binding to montmorillonite followed by kaolinite and sea sand. Interestingly, Cel5H had higher pI value of 9.24 than other proteins (5.2-5.7). Cel5H binding to montmorillonite was shown to be negatively affected below pH 3 and above pH 9. Infrared absorption spectra of the Cel5H-montmorillonite complexes showed distinct peaks for clay minerals and bound proteins. Furthermore, database survey of soil bacterial extracellular enzymes revealed that Bacillus species enzymes had higher pI than other soil bacterial enzymes.


Assuntos
Bacillus licheniformis/enzimologia , Celulases/metabolismo , Argila , Bases de Dados de Proteínas , Ponto Isoelétrico , Minerais/metabolismo , Microbiologia do Solo , Celulases/genética , Clonagem Molecular , Hidrólise , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
4.
Appl Biochem Biotechnol ; 190(3): 839-850, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31502107

RESUMO

This work aims to study the immobilization of Candida rugosa lipase (CRL) onto corn straw residue. For this purpose, chemical, morphological, and textural characteristics of the corn straw; immobilization process by adsorption; and immobilized enzyme activity and storage stability were evaluated. The corn straw presented isoelectric point of 7.0, surface with hydroxyl bands being favorable to the immobilization process. An irregular surface was also observed with fibers and pores, which are mesoporous and macroporous, characteristics that demonstrate efficiency in mass transfer mechanisms. Upon immobilization, it was observed that adsorption velocity is proportional to the square of the available adsorption sites (pseudo-second-order), and that the immobilization occurs in monolayers (Langmuir isotherm). The adsorption process was favorable and considered as a chemical adsorption mechanism. After immobilization, the optimum temperature increased, the optimum pH reduced, and the affinity of the biocatalyst for the substrate decreased. Corn straw derivative demonstrated good thermal stability. Regarding storage stability, there was approximately 12% loss of activity after 60 days of storage at 4 °C. Considering that no treatment was applied to the corn straw, this result is satisfactory and shows good affinity between this support and CRL.


Assuntos
Enzimas Imobilizadas/metabolismo , Lipase/metabolismo , Zea mays/química , Adsorção , Candida/enzimologia , Temperatura Baixa , Estabilidade Enzimática , Ponto Isoelétrico
5.
Biophys Chem ; 256: 106269, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31733408

RESUMO

The distribution of the protein isoelectric point (pI) in the protein-protein interaction (PPI) networks across the domains of life has not been investigated yet. This work attempts to correlate the pI with the number of direct interacting partners in the experimentally supported networks involving 226.085 PPIs from 14 various organisms including human, mouse, yeast, bacteria, viruses and 53.606 virus-host interactions. The results showed that the acidic proteins (pI<3) have the highest average number of interactions in eukaryotes, while in bacteria more neutral proteins. On the contrary, the basic proteins (pI>11) have the lowest average number of interactions in human, mouse, yeast, bacteria and human-viral interactomes and the highest average in intraviral interactomes. We examined the correlation of the pI of the interacting partners by calculating the assortativity index of various PPI networks. We found that the interactions between the acidic, neutral and basic proteins have a fairly random mix, implying weak if any association between the acidic and basic proteins. Furthermore, protein features such as biological function, structurally order and disorder, subcellular localization, and homodimerization were classified according to pI in prokaryote and eukaryote proteomes.


Assuntos
Mapas de Interação de Proteínas , Proteínas/química , Animais , Bactérias/metabolismo , Bases de Dados de Proteínas , Humanos , Ponto Isoelétrico , Camundongos , Saccharomyces cerevisiae/metabolismo , Vírus/metabolismo
6.
Se Pu ; 37(10): 1090-1097, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642288

RESUMO

A partially filled monolith was prepared by in situ polymerization, and then carrier ampholytes (CAs, pH 3-10) were immobilized on its surface. For effective utilization of capillary isoelectric focusing (cIEF) with the monolithic immobilized pH gradient (M-IPG), a new online platform was established by the introducing of an eight-way injection valve, a three-way valve and a cross-shaped unit. Besides, a capillary coated with hydroxypropyl cellulose (HPC capillary) was prepared and used to determine the isoelectric points (pI) of trastuzumab and etanercept. In parallel, using the newly built capillary isoelectric focusing platform, the pI values of trastuzumab and etanercept were measured with the M-IPG column, and compared with the results obtained using the HPC capillary. It was found that these two cIEF columns can be effectively used to separate proteins and determine the pI values of monoclonal antibodies and fusion proteins in protein drugs. Moreover, the measured pI values were consistent with those estimated using the HPC capillary.


Assuntos
Focalização Isoelétrica , Proteínas/química , Força Próton-Motriz , Anticorpos Monoclonais/química , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Polimerização
7.
Colloids Surf B Biointerfaces ; 184: 110424, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31542642

RESUMO

Deposition kinetics of fibrinogen/polystyrene particle complexes on mica and the silicon/silica substrates was studied using the direct optical and atomic force microscopy. Initially, basic physicochemical characteristics of fibrinogen and the microparticles were acquired using the dynamic light scattering and the electrophoretic mobility methods, whereas the zeta potential of the substrates was determined using the streaming potential measurements. Subsequently an efficient method for the preparation of fibrinogen/polymer microparticle complexes characterized by controlled coverage and molecule orientation was developed. It was demonstrated that for a lower suspension concentration the complexes are stable for pH range 3-9 and for a large concentration for pH below 4.5 and above 5.5. This enabled to carry out thorough pH cycling experiments where their isoelectric point was determined to appear at pH 5. Kinetic measurements showed that the deposition rate of the complexes vanished at pH above 5, whereas the kinetics of the positively charged amidine particles, used as control, remained at maximum for pH up to 9. These results were theoretically interpreted using the hybrid random sequential adsorption model. It was confirmed that the deposition kinetics of the complexes can be adequately analyzed in terms of the mean-field approach, analogously to the ordinary colloid particle behavior. This is in contrast to the fibrinogen molecule behavior, which efficiently adsorb on negatively charged substrates for the entire range pHs up to 9.7. These results have practical significance for conducting efficient immunoassays governed by the specific antigen/antibody interactions.


Assuntos
Silicatos de Alumínio/química , Micropartículas Derivadas de Células/química , Fibrinogênio/química , Poliestirenos/química , Adsorção , Coloides/química , Difusão Dinâmica da Luz/métodos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Cinética , Microscopia de Força Atômica/métodos , Concentração Osmolar , Dióxido de Silício/química , Propriedades de Superfície
8.
Mater Sci Eng C Mater Biol Appl ; 105: 110033, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546405

RESUMO

Effective protein adsorption has attracted attention for broad application in the biomedical field. In this study, we introduce the synthesis of a TEMPO-oxidized cellulose nanofiber (TOCN) decorated macroporous SiO2 (TOCN@macroporous SiO2) particle and its protein adsorption performance. The TOCN@macroporous SiO2 particles have a unique cellulose nanofiber network structure on the macroporous, highly-negative zeta potential (-62 ±â€¯2 mV) and high surface area (30.8 m2/g) for dried-state cellulose based particles. These characteristics provide sites that are rich in electrostatic interaction to exhibit an outstanding adsorption capacity of lysozyme (1865 mg/g). Furthermore, the TOCN@macroporous SiO2 particles have remarkably high reusability (>90% adsorption capacity) and good release of adsorbate (>80%) after 10 times of use. The material proposed in this paper has the potential for application in drug delivery, protein adsorption, biosensors, and other biomedical fields.


Assuntos
Celulose/química , Óxidos N-Cíclicos/química , Muramidase/isolamento & purificação , Nanofibras/química , Dióxido de Silício/química , Adsorção , Ponto Isoelétrico , Cinética , Nanofibras/ultraestrutura , Nitrogênio/química , Oxirredução , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Mater Sci Eng C Mater Biol Appl ; 105: 110042, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546440

RESUMO

Influences of proteins on degradation of magnesium alloys are of great significance but not well understood. In particular the roles of amino acids, the basic unit of proteins in regulating the progress of biodegradation of magnesium based materials remain unclear. This study aims to investigate the impacts of alanine, glutamic acid and lysine on degradation of pure magnesium in phosphate buffer solution through SEM, XPS, FTIR, potentiodynamic polarisation curves, electrochemical impedance spectroscopy and immersion tests. The changed contents of amino acids in solutions were detected by UV-vis spectrophotometer. Results demonstrate that the charges of the selected amino acids imposed significant contribution to suppressing the degradation of pure magnesium in phosphate buffer solution. The presence of amino acids led to the formation of phosphate-based corrosion products, increasing free corrosion potential, and reduction in corrosion current density and solution pH depending on their isoelectric points and molecular structures. A plausible corrosion mechanism organised by amino acids on pure magnesium was proposed.


Assuntos
Aminoácidos/química , Magnésio/química , Fosfatos/química , Tampões (Química) , Corrosão , Espectroscopia Dielétrica , Eletroquímica , Humanos , Hidrogênio/análise , Ponto Isoelétrico , Conformação Molecular , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X
10.
BMC Mol Cell Biol ; 20(1): 36, 2019 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-31429701

RESUMO

BACKGROUND: Whole-proteome distributions of protein isoelectric point (pI) values in different organisms are bi- or trimodal with some variations. It was suggested that the observed multimodality of the proteome-wide pI distributions is associated with subcellular localization-specific differences in the local pI distributions. However, the factors responsible for variation of the intracellular localization-specific pI profiles have not been investigated in detail. RESULTS: In this work, we explored proteome-wide pI distributions of 32,138 human proteins predicted to reside in 10 subcellular compartments, as well as the pI distributions of experimentally observed lysosomal and Golgi proteins. The distributions were found to differ significantly, although all of them adhered to the major recurrent bimodal pattern. Grossly, acid-biased and alkaline-biased patterns with various minor statistical features were observed at different subcellular locations. Bioinformatics analysis revealed the existence of strong statistically significant correlations between protein pI and subcellular localization. Most markedly, protein pI was found to correlate positively with nuclear and mitochondrial locations and negatively with cytoskeletal, cytoplasmic, lysosomal and peroxisomal environment. Further analysis demonstrated that subcellular compartment-specific pI distributions are greatly influenced by local pH and organelle membrane charge. Multiple nonlinear regression analysis identified a polynomial function of the two variables that best fitted the mean pI values of the localization-specific pI distributions. A high coefficient of determination calculated for this regression (R2 = 0.98) suggests that local pH and organelle membrane charge are the major factors responsible for variation of the intracellular localization-specific pI profiles. CONCLUSIONS: Our study demonstrates that strong correlations exist between protein pI and subcellular localization. The specific pI distributions at different subcellular locations are defined by local environment. Predominantly, it is the local pH and membrane charge that shape the organelle-specific protein pI patterns. These findings expand our understanding of spatial organization of the human proteome.


Assuntos
Membrana Celular/metabolismo , Proteoma/metabolismo , Complexo de Golgi/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Lisossomos/metabolismo , Análise de Regressão , Frações Subcelulares/metabolismo
11.
Bioelectrochemistry ; 130: 107200, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31382227

RESUMO

In this study, a microbial electrochemical system (MES) was employed to investigate the effect of isoelectric point (IEP) on cheese whey wastewater treatment. The experiments were carried out in a bioreactor equipped with a semicircular carbon cloth and stainless steel electrodes as anode and cathode, respectively. The effects of IEP, whey protein concentration, electrical current, and time were studied. The IEP of the whey protein was determined at pH 5.9. The optimum electrical current was obtained at 6 mA for synthetic cheese whey wastewater. The results of rotary exponential doping showed that the third structure of proteins chenges to the second structure at the IEP. The highest protein removal (98%) was obtained at pH 6. The results showed that 76%, 83%, and 98% protein removal were achieved at 2, 4, and 8 h, respectively.


Assuntos
Reatores Biológicos/microbiologia , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/instrumentação , Proteínas do Soro do Leite/isolamento & purificação , Análise da Demanda Biológica de Oxigênio , Queijo/análise , Desenho de Equipamento , Tecnologia de Alimentos , Ponto Isoelétrico
12.
BMC Genomics ; 20(1): 631, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31382875

RESUMO

BACKGROUND: Cell contain diverse array of proteins with different molecular weight and isoelectric point (pI). The molecular weight and pI of protein play important role in determining the molecular biochemical function. Therefore, it was important to understand the detail regarding the molecular weight and pI of the plant proteins. RESULTS: A proteome-wide analysis of plant proteomes from 145 species revealed a pI range of 1.99 (epsin) to 13.96 (hypothetical protein). The spectrum of molecular mass of the plant proteins varied from 0.54 to 2236.8 kDa. A putative Type-I polyketide synthase (22244 amino acids) in Volvox carteri was found to be the largest protein in the plant kingdom. However, Type-I polyketide synthase was not found in higher plant species. Titin (806.46 kDa) and misin/midasin (730.02 kDa) were the largest proteins identified in higher plant species. The pI and molecular weight of the plant proteins showed a trimodal distribution. An acidic pI (56.44% of proteins) was found to be predominant over a basic pI (43.34% of proteins) and the abundance of acidic pI proteins was higher in unicellular algae species relative to multicellular higher plants. In contrast, the seaweed, Porphyra umbilicalis, possesses a higher proportion of basic pI proteins (70.09%). Plant proteomes were also found to contain selenocysteine (Sec), amino acid that was found only in lower eukaryotic aquatic plant lineage. Amino acid composition analysis showed Leu was high and Trp was low abundant amino acids in the plant proteome. Additionally, the plant proteomes also possess ambiguous amino acids Xaa (unknown), Asx (asparagine or aspartic acid), Glx (glutamine or glutamic acid), and Xle (leucine or isoleucine) as well. CONCLUSION: The diverse molecular weight and isoelectric point range of plant proteome will be helpful to understand their biochemical and functional aspects. The presence of selenocysteine proteins in lower eukaryotic organism is of interest and their expression in higher plant system can help us to understand their functional role.


Assuntos
Plantas/química , Proteoma/química , Animais , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Ponto Isoelétrico , Peso Molecular , Plantas/metabolismo , Proteoma/metabolismo , Proteômica , Selenocisteína/química
13.
Int J Mol Sci ; 20(16)2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31412541

RESUMO

The extraction and enzymatic hydrolysis of collagen from sheepskins at different times of hydrolysis (0, 10, 15, 20, 30 min, 1, 2, 3 and 4 h) were investigated in terms of amino acid content (hydroxyproline), isoelectric point, molecular weight (Mw) by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method, viscosity, Fourier-transform infrared (FTIR) spectroscopy, antioxidant capacity by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, thermal properties (Differential Scanning Calorimetry) and morphology by scanning electron microscopy (SEM) technique. The kinetics of hydrolysis showed an increase in the protein and hydroxyproline concentration as the hydrolysis time increased to 4 h. FTIR spectra allowed us to identify the functional groups of hydrolysed collagen (HC) in the amide I region for collagen. The isoelectric point shifted to lower values compared to the native collagen precursor. The change in molecular weight and viscosity from time 0 min to 4 h promoted important antioxidant activity in the resulting HC. The lower the Mw, the greater the ability to donate an electron or hydrogen to stabilize radicals. From the SEM images it was evident that HC after 2 h had a porous and spongy structure. These results suggest that HC could be a good alternative to replace HC from typical sources like pigs, cows and fish.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Colágeno/química , Peptídeos/química , Peptídeos/farmacologia , Aminoácidos/química , Animais , Hidrólise , Ponto Isoelétrico , Peso Molecular , Ovinos , Pele/química , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Viscosidade
14.
Colloids Surf B Biointerfaces ; 183: 110392, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31394423

RESUMO

In this study, we evaluated the adsorption of proteins to 2,2,6,6-tetramethylpiperidine-1-oxyl oxidized cellulose nanofibers (TOCNs) and their structures on the TOCN surface. TOCNs derived from bleached pulp are as thin as 4 nm and have a very high specific surface area and a high density of surface carboxyl groups. The adsorption of two model proteins (lysozyme (Lyz) and bovine serum albumin (BSA)), which is driven by electrostatic attraction between the positively charged proteins and the negatively charged TOCN surface bearing ionized carboxyl groups, is demonstrated to occur only at pH values below their isoelectric points. Notably, pristine BSA and Lyz retain their native structures after adsorption onto TOCN, which is ascribed to the very low width of TOCN, and consequently the low area of contact between the protein and cellulose fiber. Thus, this work paves the way to the fabrication of TOCN-based biomaterials with the retention of the structure of the adsorbed proteins.


Assuntos
Celulose/química , Óxidos N-Cíclicos/química , Muramidase/química , Nanofibras/química , Soroalbumina Bovina/química , Adsorção , Animais , Bovinos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Modelos Moleculares , Oxirredução , Conformação Proteica em alfa-Hélice , Eletricidade Estática , Propriedades de Superfície , Resistência à Tração
15.
Int J Nanomedicine ; 14: 4895-4909, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31456636

RESUMO

Introduction: Insulin is given by injection, because when administered orally, it would be destroyed by enzymes in the digestive system, hence only about 0.1% reaches blood circulation. The purpose of the present study was to use pH sensitive polyelectrolyte methyl methacrylate (MMA)/itaconic acid (IA) nanogels as carriers in an attempt to improve absorption of insulin administered orally. Methods: Insulin (Ins) was incorporated into the MMA/IA nanogels (NGs) using the polyelectrolyte complexation (PEC) method to form Ins/NGs-PEC. Several parameters, including Ins:NGs ratio, pH, incubation time and stirring rate were optimized during preparation of InsNGs-PEC. The prepared formulations were characterized in terms of particle size (PS), polydispersity index (PdI), zeta potential (ZP) and percent entrapment efficiency (% EE). Results: The optimized InF12 nanogels had a PS, PdI, ZP and %EE of 190.43 nm, 0.186, -16.70 mV and 85.20%, respectively. The InF12 nanogels were lyophilized in the presence of different concentrations of trehalose as cryoprotectant. The lyophilized InF12 containing 2%w/v trahalose (InF12-Tre2 nanogels) was chosen as final formulation which had a PS, PdI, ZP and %EE of 430.50 nm, 0.588, -16.50 mv and 82.10, respectively. The in vitro release of insulin from InF12-Tre2 nanogels in the SGF and SIF were 28.71% and 96.53%, respectively. The stability study conducted at 5±3°C for 3 months showed that lnF12-Tre2 nanogels were stable. The SDS-PAGE assay indicated that the primary structure of insulin in the lnF12-Tre2 nanogels was intact. The in-vivo study in the diabetic rats following oral administration of InF12-Tre2 nanogels at a dose of 100 IU/kg body weight reduced blood glucose level significantly to 51.10% after 6 hours compared to the control groups. Conclusions: The pH sensitive MMA/IA nanogels are potential carriers for oral delivery of insulin as they enhanced the absorption of the drug.


Assuntos
Liofilização , Insulina/administração & dosagem , Polieletrólitos/química , Polietilenoglicóis/administração & dosagem , Polietilenoimina/administração & dosagem , Administração Oral , Animais , Crioprotetores/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Masculino , Nanogéis , Ratos Sprague-Dawley , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Fatores de Tempo
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 221: 117204, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31158760

RESUMO

A novel fluorescence probe based on graphene-aminofluorescein (GAF) for sensing glutamate is prepared by modifying graphene oxide (GO) with 5-aminofluorescein (AF), and shows high sensitivity and selectivity. The strong fluorescence of the GAF probe is quenched in the presence of glutamate, and the quenching exhibits a good linear relationship with the glutamate concentration within the range of 1-45 mg/L. In bovine serum, the accurate quantitation of glutamate is possible within the range of 6 mg/L to 30 mg/L. At the pH of 3.32 (close to the isoelectric point of glutamate), GAF can selectively detect glutamate in preference to other amino acids. The high sensitivity and specificity of this sensor enable a new method for the detection of glutamate in aqueous solutions and serums.


Assuntos
Corantes Fluorescentes/química , Ácido Glutâmico/análise , Grafite/química , Animais , Bovinos , Ácido Glutâmico/sangue , Ácido Glutâmico/química , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Microscopia de Força Atômica , Nanoestruturas/química , Óxidos/química , Espectroscopia Fotoeletrônica , Sensibilidade e Especificidade , Solubilidade , Soluções/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Água/análise , Água/química
17.
Mater Sci Eng C Mater Biol Appl ; 102: 373-390, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147009

RESUMO

Tissue regeneration is witnessing a significant surge in advanced medicine. It requires the interaction of scaffolds with different cell types for efficient tissue formation post-implantation. The presence of tissue subtypes in more complex organs demands the co-existence of different biomaterials showing different hydrolysis rate for specialized cell-dependent remodeling. To expand the available toolbox of biomaterials with sufficient mechanical strength and variable rate of enzymatic degradation, a cold-adapted methacrylamide gelatin was developed from salmon skin. Compared with mammalian methacrylamide gelatin (GelMA), hydrogels derived from salmon GelMA displayed similar mechanical properties than the former. Nevertheless, salmon gelatin and salmon GelMA-derived hydrogels presented characteristics common of cold-adaptation, such as reduced activation energy for collagenase, increased enzymatic hydrolysis turnover of hydrogels, increased interconnected polypeptides molecular mobility and lower physical gelation capability. These properties resulted in increased cell-remodeling rate in vitro and in vivo, proving the potential and biological tolerance of this mechanically adequate cold-adapted biomaterial as alternative scaffold subtypes with improved cell invasion and tissue fusion capacity.


Assuntos
Acrilamidas/química , Materiais Biocompatíveis/química , Temperatura Baixa , Gelatina/química , Engenharia Tecidual/métodos , Animais , Bovinos , Proliferação de Células , Força Compressiva , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Hidrogéis/química , Hidrólise , Ponto Isoelétrico , Cinética , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica , Salmão , Eletricidade Estática
18.
J Am Soc Mass Spectrom ; 30(8): 1389-1395, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31077092

RESUMO

Mass spectrometry is frequently used to determine protein complex topology. By combining in-solution and gas-phase dissociation measurements, information can be indirectly inferred about the original composition of the protein complex. Although the mechanisms behind gas-phase complex dissociation are becoming more established, protein complex dissociation is not always predictable. Here, we looked into the effect of the protein subunits pI on complex dissociation. We chose two structurally similar, hexameric protein complexes that consist of a ring of alternating alpha and beta subunits. For one complex, allophycocyanin, the alpha and beta subunits are structurally similar, almost identical in mass, but have distinct pIs. In contrast, the other complex, phycoerythrin, is structural similar to allophycocyanin, yet the subunits have identical pIs. As predicted based on the structural arrangement, dissociation of phycoerythrin resulted in the observation of both the alpha and beta monomeric subunits in the mass spectrometer. However, for allophycocyanin, the results differed dramatically, with only the alpha monomeric subunit being detected upon gas-phase dissociation. Together, the results highlighted the importance of considering the isoelectric points of individual subunits within a protein complex when using tandem mass spectrometry data to elucidate protein complex topology.


Assuntos
Proteínas de Bactérias/química , Ficobiliproteínas/química , Proteínas de Plantas/química , Porphyridium/química , Spirulina/química , Sequência de Aminoácidos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Espectrometria de Massas , Modelos Moleculares , Conformação Proteica , Multimerização Proteica , Subunidades Proteicas/química
19.
Carbohydr Polym ; 215: 358-365, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30981365

RESUMO

Hyaluronic acid (HA) is a natural polysaccharide possesses outstanding physiological activities. In this work, HA was activated as a novel collagen modifier via the esterification reaction between N-hydroxysuccinimide (NHS) and the carboxyl groups of HA. Both of Fourier transform infrared spectroscopy (FTIR) and 1H- nuclear magnetic resonance (NMR) spectra indicated the successful synthesis of HA-NHS esters. As reflected by FTIR, circular dichroism (CD) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), collagens modified with HA-NHS ester maintained its intact triplex structure with larger molecular weight. The resultant polyanionic collagen displayed an excellent dissolubility in the neutral water to form a clear solution, due to the significantly lower isoelectric point values (3.8-4.4) compared with that of the native collagen (7.1). In addition, the thermal transition temperature of collagen was significantly increased (16 °C) after modifying with HA-NHS esters. Both of the aggregation morphology and rheological property exhibited high dependence on the NHS/COOH ratio of HA-NHS esters, as reflected by field-emission scanning electron microscopy (FESEM) and rheological test, respectively. The present study offered a novel dual-functional modifier based on the design of HA-NHS ester to obtain water-soluble collagen with desired thermal stability and rheological property, which will significantly widen the application range of collagen, especially in the fields of injectable biodegradable materials and cosmetics.


Assuntos
Colágeno/química , Ésteres/química , Ácido Hialurônico/química , Polímeros/química , Ponto Isoelétrico , Solubilidade , Viscosidade
20.
Food Chem ; 291: 223-230, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31006463

RESUMO

The glycation of silver carp myosin (Ms) with konjac oligo-glucomannan (KOG) of different degrees of deacetylation (DD) was investigated. As DD increased, the physico-chemical and functional properties of glycoconjugates changed. The available lysine content decreased, while grafting degree and total sulfhydryl group increased, andmeanwhile, the isoelectric point (pI) reduced. SDS-PAGE analysis indicated that glycation can be promoted as the increase of DD. The solubility increased significantly both in 0.1 M and 0.5 M NaCl solution, and the thermal stability increased when heated for 60 min at 80 °C. The emulsifying activity index (EAI) and emulsifying stability index (ESI) increased as well. These results showed that the highly deacetylated KOG (DKOG) was easier to glycate with myosin, leading to a great improvement in functional properties of myosin. It can be suggested that the reduction in steric hindrance of DKOG as a result of removal of acetyl groups facilitated the glycation.


Assuntos
Carpas/metabolismo , Mananas/metabolismo , Miosinas/metabolismo , Acetilação , Animais , Eletroforese em Gel de Poliacrilamida , Glicosilação , Ponto Isoelétrico , Miosinas/química , Estabilidade Proteica , Compostos de Sulfidrila/análise , Temperatura
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