• Applied Biological Chemistry
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• v.34 no.1
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• pp.1-7
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• 1991

Optimum conditions for hydrolysis of sunflower seed by pepsin and for plastein formation by pepsin were determined. The optimum conditions for hydrolysis of sunflower seed were pH 1.5, $45^{\circ}C$, enzyme concentration 2%, substrate concentration 2%, and hydrolysis time 24hr. The optimum conditions for sunflower seed-plastein formation were 50% substrate, pH 4.5, $50^{\circ}C$, 0.25% pepsin and 18hrs reaction time. To verify plastein fromation from concentrated prptic hydrolysate of sunflower seed, thin layer chromatography was performed. The TLC pattern of concentrated peptic hydrolysate of sunflower seed was different from that of its plastein. The TLC pattern of concentrated peptic bydrolysate of sunflower seed and at of its plastein indicated that plastein was different material from the hydrolysate.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.120-126
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• 2006

Fish backbone, a major by-product in the fish processing industry, accounts for about 15% of whole fish weight. In this study, recovery of bioavailable calcium from Alaska pollack (Theragra chalcogramma) backbone by-products using enzymatic hydrolysis was investigated. Finely ground fish backbones were hydrolyzed with two proteolytic enzymes (pepsin and protease) to obtain soluble calcium from the by-products. The pepsin digest had a higher degradation efficiency (88%) than protease. Four different concentrations of the fish backbone calcium (100, 250, 500 and 1000 mg/L) prepared by the pepsin digest were treated with $Na_2HPO_4$ at a concentration gradient (0, 1, 2, 4, 8, 10, 15 and 20 mM) to evaluate their solubility, revealing that solubilities of the fish backbone calcium were superior to those of $CaCl_2$ at all the calcium and $Na_2HPO_4$ concentrations. Among the tested concentrations the highest solubility was found in the pepsin digest containing a calcium concentration of 1000 mg/L. Thus, hydrolyzing with pepsin is an effective mode of recovering bioavailable calcium from Alaska pollack fish backbones.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.39-45
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• 1993

The effects of enzymatic modification with pepsin and actinidin was studied on molecular weight distributions and functional properties of hydrolysates from soy protein isolate (SPI) differing in degree of hydrolysis. The hydrolyzed SPI by pepsin showed 41.5% degree of hydrolysis after 5 min, and maximum hydrolysis was obtained after 2 hours. Actinidin hydrolyzed SPI 26.71% degree after 1 hour. On SDS-PAGE, native SPI showed 9 distinguishable bands on SDS-PAGE gel. Pepsin treated SPI showed one broad band in the lower part of gel. This band was shifted further to the bottom of the gel and became faint as hydrolysis time increased. While actinidin treated SPI showed different SDS-PAGE pattern from pepsin. However PAGE patterns were similar with pepsin and actinidin treated groups. With pepsin treatment, solubility of SPI distinctively increased around isoelectric point(pI). Emulsifying activity (EA) and emulsifying stability (ES) showed marked increase over pH range of $3.0{\sim}8.0$. 5 min modified group had most excellent foam expansion (FE). Foam stability (FS) was increased as pepsin treatment time increased at pI. With actinidin treatment, solubility was increased. 60 min modified SPI had the most effective EA at pH 4.5. However ES was not effected by actinidin treatment. 5 min modified group was most effect in FE. FS was higher at alkaline pH.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.706-711
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• 2009

Lysozyme was treated with digestive enzymes and the production of interleukin 8 (IL-8) was measured in Caco-2 cell with the peptides from lysozyme upon stimulating with lipopolysaccharide (LPS) to investigate the overall anti-inflammatory activity of lysozyme when it is in digestive tracts. Lysozyme reduced IL-8 production, and the peptides from pepsin hydrolysis of lysozyme had the similar effect. The products of trypsin digestion of lysozyme had no effect on the reduction of IL-8 production while those of pepsin-trypsin hydrolysis did. The effectiveness of lowering IL-8 production was not different by time of the peptide addition. When Caco-2 cells were pre-incubated with peptides for 24 hr, the reduction effects were observed from the peptides from pepsin hydrolysis, indicating that some of the peptides are still remaining in the cells. Therefore, it can be concluded that the IL-8 reduction effect of lysozyme against LPS still remained even after the pepsin and trypsin hydrolysis.

• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.155-160
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• 1970

The kinetics of the pepsin-catalyzed hydrolysis of N-carbobenzoxy-L-glutamyl-L-tyrosine at pH 3.5 and $37^{\circ}C$ were determined by a spectrophotometric technique. The pepsin used was further purified on a Sephadex G-75 column. The kinetics data were Km = l.7 ${\times}10^{-3}M,\;-{\Delta}F^{\circ}$ = 3.99Kcal/mole, and $k^3=\;2.1{\times}10^{-2}\;sec^{-1}$. An analysis of the above data and other investigators' data obtained from some dipeptides led to the following conclusions. (1) Phenylalanyl residues in a synthetic peptide are bound to pepsin more strongly than glutamyl or tyrosyl residues, supporting the theory that a part of the binding region of the active center is hydrophobic. (2) Dipeptides are bound to pepsin principally through their side chains and the binding involves both side-chain residues. (3) The nature of amino acids in dipeptides $R_2-R_1,\;affect\;the\;k_3$ values.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.304-308
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• 2006

This study was performed to understand the behavior of protein mobility and intensity of enzymatic hydrolysis according to crosslinking of sodium caseinate, whey protein isolate, skim milk and whole milk powders with or without transglutaminase (TGase, w/w = 200 : 1) at $38^{\circ}C$. Whey protein was limited to crosslinking and skim milk was relatively more increased in high molecular polymer than whole milk. The degree of crosslinking decreased in the order of sodium caseinate>skim milk>whole milk>whey protein isolate. The SDS-PAGE results indicated that main bands of TGase treated samples had a high mobility and formed bands of molecular weights below 15 kDa by hydrolysis with pepsin after 10 min of reaction time. However, ${\beta}-lactoglobulin$ showed remarkable stability against pepsin hydrolysis treated with and without TGase. The high molecular polymers were easily hydrolyzed with digestive enzymes in vitro experiment. These results suggested that novel dairy products using TGase would have no special digestive problem in human body.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.706-711
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• 1992

Silkworm larvae protein concentrate was partially hydrolyzed at $50^{\circ}C$ by papain at pH 2.0 and pepsin at pH 7.0 for 10min and 60min and the effect of enzymatic modification on the functional properties of silkworm larvae protein concentrate was examined. The degrees of hydrolysis measured by TCA-soluble nitrogen content were 10.2% and 19.2% when hydrolyzed by pepsin for 10min and 60min. The nitrogen solubility in water and 0.03M $CaCl_2$ was increased with increasing the degree of hydrolysis, and bulk density, water and oil absorption were also enhanced by enzymatic hydrolysis when compared with the control.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.87-96
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• 1994

This study was carried out to investigate the effect of hydrolysis by proteolytic enzymes on the functional properties of sesame protein concentrate. Sesame protein concentrate was hydrolyzed with papain, pepsin and trypsin to obtain 10% and 20% degree of hydrolysis. The nirogen solubility in water was increased with increasing the degree of hydrolysis. Bulk density was increased by enzymatic hydrolysis but water absorption capacity was increased only in the case of pepsin-hydrolyzed SPC. Higher fat absorption capacity was found in SPC with 10% DH than SPC with 20% DH. Emulsifying activity was also increased by enzymatic hydrolysis except SPC with 10% DH by papain.

• Journal of the Korean Chemical Society
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• v.13 no.3
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• pp.233-240
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• 1969

The synthesis is described of new pepsin substrates of benzyloxycarbonyl-glycyl-L-tyrosyl-L-phenylalanyl-glycine ethyl ester and benzyloxycarbonyl-glycyl-L-tyrosyl-L-phenylalanyl-glycine for studies on the specificity of pepsin, and thin layer chromatographic examination of the peptides prepared showed the new substrates are homogeneous and also, same examination of the incubation mixtures showed that two synthetic substrates are cleaved by pepsin at the L-tyrosyl-L-phenylalanyl bond and hydrolysis of these substrates by pepsin is achieved without transpeptidation. It is found that synthetic peptides are moderately soluble with the amount of the substrate up to a concentration of 0.7 mM in aqueous sodium citrate buffers (0.04 M) in the pH range 1.8-4.0, thus obviating the necessity for the adding of an organic solvent in the assay mixture. The kinetic parameters for synthetic substrates are tabulated in the following table. The data in the table indicate that the susceptibility of synthetic peptides to peptic hydrolysis are relatively large and the change of the carboxyl-terminal group of synthetic substrate from glycine ethyl ester to glycine causes a small decrease in the susceptibility of the L-tyrosyl-L-phenylalanyl bond.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.151-157
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• 2014

This study investigated the effects of three proteases (trypsin, pepsin and chymotrypsin) on the hydrolysis efficiency of porcine placenta and the molecular weight (Mw) distributions of the placental hydrolysates. Because placenta was made up of insoluble collagen, the placenta was gelatinized by applying thermal treatment at $90^{\circ}C$ for 1 h and used as the sample. The placental hydrolyzing activities of the enzymes at varying concentrations and incubation times were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography (GPC). Based on the SDS-PAGE, the best placental hydrolysis efficiency was observed in trypsin treatments where all peptide bands disappeared after 1 h of incubation as compared to 6 h of chymotrypsin. Pepsin hardly hydrolyzed the placenta as compared to the other two enzymes. The Mw distribution revealed that the trypsin produced placental peptides with Mw of 106 and 500 Da. Peptides produced by chymotrypsin exhibited broad ranges of Mw distribution (1-20 kDa), while the pepsin treatment showed Mw greater than 7 kDa. For comparisons of pre-treatments, the subcritical water processing (37.5 MPa and $200^{\circ}C$) of raw placenta improved the efficiency of tryptic digestions to a greater level than that of a preheating treatment ($90^{\circ}C$ for 1 h). Consequently, subcritical water processing followed by enzymatic digestions has the potential of an advanced collagen hydrolysis technique.