Mixture Of Pepsin Research Articles

Improvement of Microbial Quality, Physicochemical Properties, Fatty Acids Profile, and Shelf Life of Basa (Pangasius bocourti) Fillets during Chilling Storage Using Pepsin, Rosemary Oil, and Citric Acid.

Meat discoloration, lipid oxidation, and undesirable texture are inevitable phenomena in basa fish fillets during storage, which in turn limits their exportation as well as decreases consumer acceptability. In addition, increasing consumers' requirements for high-quality, minimally processed, and ready-to-cook fish fillets with an extended shelf-life is a great challenge, particularly with lifestyle changes. Accordingly, this study aimed to improve the quality, lipid stability, fatty acid profile, and lipid nutritional quality indices (LNQI) of basa fish fillets during chilling storage at 4 °C for 15 days using pepsin enzyme (E, 0.1%), rosemary oil (R, 0.5%), citric acid (CA, 0.5%), and their combination (0.1% E + 0.5% R; 0.1% E + 0.5% CA; and 0.1% E + 0.5% R + 0.5% CA). Our results revealed that all treated samples exhibited a significant increase in protein content, a significant decrease in fat content, and a marked reduction in pH, total volatile base nitrogen (TVBN), thiobarbituric acid (TBA), free fatty acids, and shear force (SF) values in comparison to control ones. Moreover, significant improvements in sensory scores, color stability, fatty acid profile, LNQI, and microbial quality of all treated samples were observed. Such findings were more pronounced in samples treated with a mixture of pepsin, rosemary, and citric acid (TVBN: 2.04 vs. 6.52 mg%; TBA: 0.40 vs. 2.68 mg malonaldehyde/Kg; and SF: 8.58 vs. 19.51 Kgf). Based on the obtained results, there was an extension for the shelf life of all treated basa fish fillet samples, especially in samples treated with a mixture of pepsin, rosemary, and citric acids when compared with the control samples (˃15 days versus 10 days). Additionally, eucalyptol, camphor, isoborneol, and α-pinene are the main components of rosemary, with great antioxidant and antimicrobial activity. In conclusion, the mixture of pepsin, rosemary, and citric acid can be applied easily in the seafood industry and at the household level to provide ready-to-cook fish fillets of high quality with great health benefits.

Interaction between gastric enzyme pepsin and tetradecyltrimethylammonium bromide in presence of sodium electrolytes: Exploration of micellization behavior

Pepsin is a proteolytic enzyme used in the treatment of digestive disorders. In this study, we investigated the physicochemical properties of the tetradecyltrimethylammonium bromide (TTAB) and pepsin protein mixture in various sodium salt media within a temperature range of 300.55–320.55 K with 5 K intervals. The conductometric study of the TTAB+pepsin mixture revealed a reduction in the critical micelle concentration (CMC) in electrolyte media. The micellization of TTAB was delayed in the presence of pepsin. The CMC of the TTAB + pepsin mixture was found to depend on the concentrations of electrolytes and protein, as well as the temperature variations. The aggregation of the TTAB+pepsin mixture was hindered as a function of [pepsin] and increasing temperatures, while micellization was promoted in aqueous electrolyte solutions. The negative free energy changes (∆Gm0) indicated the spontaneous aggregation of the TTAB+pepsin mixture. Changes in enthalpy, entropy, molar heat capacities, transfer properties, and enthalpy-entropy compensation variables were calculated and illustrated rationally. The interaction forces between TTAB and pepsin protein in the experimental solvents were primarily hydrophobic and electrostatic (ion-dipole) in nature. An analysis of molecular docking revealed hydrophobic interactions as the main stabilizing forces in the TTAB-pepsin complex.

Decellularized and solubilized pancreatic stroma promotes the in vitro proliferation, migration and differentiation of BMSCs into IPCs.

Bone marrow-derived mesenchymal stem cells (BMSCs) have the ability to differentiate into insulin-producing cells (IPCs). Bio-scaffolds derived from decellularized organs can act as a carrier for seed cells and may have broad applications in regenerative medicine. This study investigated the effect of native pancreatic stroma obtained from decellularized pancreas on the proliferation, migration and differentiation of BMSCs into IPCs, and explored the potential underlying molecular mechanism. The decellularized pancreas bio-scaffold was obtained by perfusion with Triton X-100/ammonium hydroxide, followed by digestion with a mixture of pepsin and hydrochloric acid to prepare the stroma solution. Islet-like cells were differentiated from BMSCs by a three-step induction method. The differences on the cytological behavior with or without stroma were evaluated by morphological observation, insulin release assay, qRT-PCR assay and western blot analysis. Our results showed that, stroma derived from decellularized pancreas could promote the proliferation and migration of BMSCs. Furthermore, the formation of IPCs could also be promoted, which possessed similar morphology to endogenous islets. During the induced differentiation process, the presence of stroma significantly increased the expression of insulin 1, insulin 2 and Pdx-1, as well as insulin release. This was accompanied by an increase in the phosphorylation of Akt and ERK in third stage cell clusters, which was prevented by the addition of the inhibitors PD98059 and LY294002, respectively. In summary, decellularized pancreatic stroma could promote the proliferation, migration and differentiation of BMSCs into IPCs, and this involved the activation of Akt and ERK signal pathways.

Cocoa-specific flavor components and their peptide precursors.

Essential precursors of the cocoa-specific roasting-flavor notes were formed during proteolysis of the cocoa vicilin-class(7S) globulin by a mixture of cocoa aspartic protease and carboxypeptidase. These could be partially purified by ligand-exchange chromatography. Many constituents of this peptide fraction were destroyed by post-treatment with pepsin, but the cocoa-specific flavor-precursor peptides were largely resistant against pepsin treatment. However, these peptides were not generated when the cocoa vicilin-class(7S) globulin was digested with a mixture of pepsin and carboxypeptidase. By nano-liquid chromatography mass spectrometry, the peptide composition of these peptide fractions were compared in order to identify the putative precursors of the cocoa-specific flavor components. These peptides were assigned to five regions of the cocoa vicilin-class(7S) globulin. Analyzing the roasting products of the different protein fractions by headspace solid-phase microextraction, followed by gas chromatography mass spectrometry, eight volatile compounds were detected, whose occurrence correlated with the sensory detection of cocoa-specific flavor notes.

Virtual screening for angiotensin I-converting enzyme inhibitory peptides from Phascolosoma esculenta

Abstract Background Many short peptides have proved to exhibit potential anti-hypertensive activity through the inhibition of the Angiotensin I-converting enzyme (ACE) activity and the regulation of blood pressure. However, the traditional experimental screening method for ACE inhibitory peptides is time consuming and costly, accompanied with the limitations as incomplete hydrolysis and peptides loss during purification process. Virtual methods with the aid of computer can break such bottle-neck of experimental work. In this study, an attempt was made to establish a library of di- and tri-peptides derived from proteins of Phascolosoma esculenta, a kind of seafood, through BIOPEP (http://www.uwm.edu.pl/biochemia/index.php/pl/biopep), and to screen highly active ACE inhibitory peptides by molecular docking with the help of LibDock module of Discovery Studio 3.5 software. Results Two hundred and eighty four (284) di- and tri-peptides, derived from P. esculenta proteins after a virtual hydrolysis with pepsin, trypsin and a mixture of pepsin and trypsin, were predicted to possess ACE inhibitory activity, among which there are 99 ACE inhibitory peptides with estimated IC50 less than 50 μM. Nine peptides were synthesized for the comparison between the estimated and the experimentally determined IC50. The results indicated that errors between the estimated and measured log(1/IC50) are all less than 1.0 unit. Conclusions Virtual method for peptide library construction and ACE inhibitory peptides screening efficiently demonstrated that P. esculenta proteins are prospect resource for food-origin ACE inhibitory peptide.

Surfactant Improves Graft Function After Gastric Acid–Induced Lung Damage in Lung Transplantation

The number of available donor lungs is still the limiting factor in lung transplantation. We have recently shown that diluted surfactant lavage during ex vivo lung evaluation improved the graft function after gastric acid aspiration. In the present study, we hypothesized that diluted surfactant administration would recondition and improve the graft function after acid aspiration-induced lung injury in a porcine model of pulmonary transplantation. Left lung injury was induced by intrabronchial administration of 1 mL/kg betaine HCl and pepsin mixture. The animals were subsequently ventilated for 24 hours. After organ retrieval, the donor lungs were stored at 4°C for 4 hours. In the control group, left lung transplantation was performed without any surfactant treatment. In the surfactant group, the recipients received intratracheal diluted surfactant lavage just before reperfusion and ventilation. During 7 hours of reperfusion, the hemodynamic and respiratory variables were recorded on an hourly basis. Surfactant lavage resulted in lower mean pulmonary artery pressure, higher mixed venous oxygen saturation, and better oxygenation compared with the control group (p = 0.001). Bronchoalveolar lavage interleukin-6 level, protein, and neutrophil percentage at the end of the experiment were significantly higher in the control group compared with the surfactant group (p = 0.03). Minimal surface tension was significantly lower in the surfactant group compared with controls (p = 0.03). These results demonstrate that application of diluted surfactant before reperfusion can be used effectively to improve the graft function from donor lungs injured by gastric acid aspiration.

Selective cleavage of pepsin by molybdenum metallopeptidase

In this study, the cleavage of protein by molybdenum cluster is reported for the first time. The protein target used is porcine pepsin. The data presented in this study show that pepsin is cleaved to at least three fragments with molecular weights of ∼23, ∼19 and ∼16kDa when the mixture of the protein and ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24·4H2O) was incubated at 37°C for 24h. No self cleavage of pepsin occurs at 37°C, 24h indicating that the reaction is mediated by the metal ions. N-terminal sequencing of the peptide fragments indicated three cleavage sites of pepsin between Leu 112-Tyr 113, Leu 166-Leu 167 and Leu 178-Asn 179. The cleavage reaction occurs after incubation of the mixture of pepsin and (NH4)6Mo7O24·4H2O) only for 2h. However, the specificity of the cleavage decreases when incubation time is longer than 48h. The mechanism for cleavage of pepsin is expected to be hydrolytic chemistry of the amide bonds in the protein backbone.

EARLY MECHANICAL VENTILATION IS DELETERIOUS AFTER ASPIRATION-INDUCED LUNG INJURY IN RABBITS

We investigated whether mechanical ventilation after aspiration is deleterious when started before surfactant therapy. Gas exchange and lung mechanics were measured in rabbits after aspiration either mechanically ventilated before or after lavage with diluted surfactant or Ringer's solution. Lung injury was induced by intratracheal instillation of 2 mL/kg of a betain/HCl pepsin mixture. After 30 min of spontaneous breathing, ventilation was started in 12 rabbits, which were then treated by lavage with diluted surfactant (15 mL/kg body weight; 5.3 mg/mL, group MVpre S) or with Ringer's solution (1 mL/kg; group MVpre R). Another 12 rabbits were treated by lavage while spontaneously breathing and were then connected to the ventilator (MVpost S and MVpost R). Sham control rabbits were mechanically ventilated for 4 h. At the end of experiment, PaO2/FiO2 ratio in MVpost S was five times higher than in MVpre S (P=0.0043). Lung mechanics measurements showed significant difference between MVpre S and MVpost S (P=0.0072). There was histopathologic evidence of decreased lung injury in MVpost S. Immediate initiation of ventilation is harmful when lung injury is induced by aspiration. Further investigations are needed to clarify whether the timing of lavage with diluted surfactant has an impact on the treatment of patients with aspiration or comparable types of direct lung injury.

Effect of a trypsin inhibitor from Dimorphandra mollis seeds on the development of Callosobruchus maculatus

Bruchid larvae cause major losses in grain legume crops throughout the world. Some bruchid species, such as the cowpea weevil, are pests that damage stored seeds. Plants synthesize a variety of molecules, including proteinaceous proteinase inhibitors, to defend themselves against attack by insects. In this work, a trypsin inhibitor (DMTI-II) isolated from Dimorphandra mollis seeds was tested for anti-insect activity against Callosobruchus maculatus larvae. The inhibitor produced ca. 67% mortality to this bruchid when incorporated into an artificial diet at a level of 1%. The doses necessary to cause 50% mortality (LD 50) and to reduce weight by 50% (ED 50) for DMTI-II were ca. 0.50% and 0.60%, respectively. The action of DMTI-II on C. maculatus larvae may involve the inhibition of trypsin-like activity of larval midgut extracts, the absence of digestion by midgut preparations or with a mixture of pepsin and papain, and its association with a chitin column and chitinous structure in the midgut of this insect.

Effect of a toxic protein isolated from zea mays seeds on the development and survival of the cowpea weevil, callosobruchus maculatus

Abstract: A new toxic glycoprotein (Zeatoxin) has been isolated from Zea mays and sequenced. The toxin is a single polypeptide chain, with Mr of 10 kDa . Zeatoxin was not digested by a mixture of pepsin and papain or by rnidgut preparations of C. maculatus. A diet of artificial seeds (final concentration, 0.25%) was lethal to 50% of C. maculatus . These results show that Zeatoxin is a new toxic glycoprotein to C. maculatus. A search in the database indicated that the N-terrninal sequence show no homology to any other known protein.

Effects of Enzyme Choice and Fractionation of Commercial Enzyme Preparations on Protein Recovery in Curd

Five different commercial milk clotting preparations (bovine rennet, calf rennet, calf rennet-porcine pepsin mixture, Mucor miebei protease, and modified Mucor miehei protease) were adjusted to equivalent milk clotting activities and then used to clot milk. Percentages of protein in the resulting wheys were compared. Calf rennet, bovine rennet, or modified Mucor miehei protease caused less loss of protein to the whey than Mucor miehei protease or calf rennet-porcine pepsin mixture. The five enzyme preparations were then fractionated by gel filtration. Fractions with milk clotting activity were pooled. Original enzyme preparations and the pooled fractions made from them were standardized to the same clotting activity, then used to coagulated milk to compare their effect on protein loss to the whey. Fractionation significantly improved protein recovery when bovine rennet and calf rennet-porcine pepsin mixture were used as coagulants but not when calf rennet, Mucor miehei protease, or modified Mucor miehei protease were used.

The preparation and assessment of a suitableMucor pusillusLindt proteinase–swine pepsin mixture for Cheddar cheese-making

SummaryA simple test procedure was used to predict the most suitable mixture of Noury rennet (Mucor pusillusLindt proteinase) and swine pepsin for Cheddar cheesemaking. Duplicate cheeses were made with 6 Noury rennet–swine pepsin mixtures and with each enzyme alone, with calf rennet as the control. There were slight differences in the course of the cheese-making process and in the yields of the cheeses. Sensory evaluation showed that the most acceptable cheeses were those made by coagulant mixtures closely similar to the predicted mixture and these were as acceptable as cheeses made with calf rennet. The survival rates of different groups of bacteria were similar in all cheeses. There were differences in the products of proteolysis in the various cheeses throughout ripening, particularly with respect to products derived from αs1-casein. The Noury rennet was characterized for the proportion of milk clotting activity associated with each of 4 components and its stability in solution was determined.

On the activation of pepsinogen

The content of carbohydrates in chromatographically pure swine pepsin and pepsinogen is shown to be negligible. Therefore the scission of carbohydrate moiety cannot trigger the activation of pepsinogen. Thermolysin at pH 5 converts swine pepsinogen into a mixture of pepsin and leucyl-pepsin which emphasizes the decisive role of limited proteolysis in the zymogen activation. The N-terminal sequence of 16 amino acids of leucyl-pepsin confirmed and essentially extended the data on homology of pepsin and rennin.

SEPARATION OF PEPSINOGEN I, PEPSINOGEN II, AND PEPSINOGEN III FROM HUMAN GASTRIC MUCOSA.

Extracts of acidified human gastric fundic mucosa have been fractionated on diethylaminoethyl cellulose to yield three pepsin fractions, which have, in order of their elution, been attributed to pepsin I, pepsin II A, and a mixture of pepsin II B and pepsin III. Acidification of previously purified pepsinogen I and pepsinogen III yields pepsin I and pepsin III, respectively. Acidification of previously purified pepsinogen II yields two distinct pepsin fractions, pepsin II A and pepsin II B. Pepsin II B and pepsin III have the same chromatographic mobility on diethylaminoethyl cellulose, but are probably not identical. Pyloric and duodenal mucosa yield only pepsin I upon acidification. Human pepsin-pepsin inhibitor complex is demonstrable as a chromatographic fraction distinct from pepsins upon fractionation of acidified dilute pepsinogen solutions with diethylaminoethyl cellulose equilibrated with acetate buffer pH 5.3.

Role of Pepsin in Experimental Production of Gastric Ulcer in the Rat.

The rôle of gastric juice in the etiology of gastric and duodenal ulcer has been stressed. The hydrochloric acid has received the major portion of attention. This investigation attempts to evaluate the relative importance of pepsin in the experimental production of gastric ulcer in the albino rat. Buchner, Siebert and Malloy reported that subcutaneous injections of histamine into fasting rats produced ulcers of the prostomach. These authors, as well as Burkle-de la Camp contended that the resultant increase of both hydrochloric acid and pepsin were responsible for the observed ulcers. It occurred to us that a more direct approach to this problem could be made with controlled feeding experiments, employing mixtures of pepsin and hydrochloric acid and hydrochloric acid alone. In such manner, we felt that the relative importance of these factors could be evaluated. A total of 58 rats of the original Wistar strain, averaging in age 4 months, were fed the Steenbock-Bills stock diet. Fresh lettuce or sliced carrots were added on feeding days. Fluids were supplied by means of stoppered flasks, with glass tube outlets, attached to the cages. The rats were then able to partake of these solutions ad lib. The first group (1) received a 20% (by weight) mixture of granular pepsin (1:10,000 Parke, Davis and Co.) in 0.3% solution of hydrochloric acid. The second group (2) received a 0.3% solution of hydrochloric acid alone. These solutions were freshly prepared every other day. One-half of each group (A) were fasted for 2 days and fed on the 3rd day; the control half of each group (B) had access to food at all times. The third group (3) received a 20% (by weight) mixture of inactivated pepsin (by heat) in 0.3% solution of hydrochloric acid, being fasted for 2 days and fed on the 3rd day.