• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.242-248
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• 1988

Plasteins were synthesized from a peptic sardine protein hydrolysate by pepsin, ${\alpha}-chymotrypsin$ pretense(from Aspergillus saitoi) and papain under the optimum conditions of previous paper. L -glutamic acid diethylester and L-leucine ethylester also were incorporated into plastein during the plastein reaction by papain. General composition, yield, molecular weight and amino acid composition were measured. The protein, ash and lipid rontent of plasteins were $81.1{\sim}88.2%$, $1.9{\sim}7.6%$ and $0.3{\sim}0.8%$, respectively. The yield of plasteins were pretense plastein 52.3%, papain plastein 44.2%, pepsin plnstein 43.6%, ${\alpha}-chymotrypsin$ plastein 43.2%. Leu -papain plastein 33. 2% and Glu - papain plastein 29.0%. The glutamic acid and leucine content in Glu -papain plastein and Leu -papain plastein were 39.0%, 37.5%, respectively. While the contents in the papain plastein were 14.3%, 7.1%, respectively. The amino acid composition of plasteins were similar to that of peptic sardine protein hydrolysate. The major molecular weight of the peptic hydrolysnte estimated by gelfilteration were 1,800 and 285, and those of plasteins were 26,000 and 9,100 for ${\alpha}-chymotrypsin$, 23,000, 10,000 and 4,300 for pepsin, 18,000 for pretense, 13,000 for papain, 29,000 for Leu -papain plastein and 19,000 for Glu -papain plastein.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.517-524
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• 1990

The solubilization and desolubilization of proteins in CTAB/hexanol/isooctane reverse micellar system were investigated for the selective separation of proteins. Several proteins were used, including bovine serum albumin (BSA), pepsin, trysin and ribonuclease-a. Most proteins could be solubilized into reverse micelles in the pH range above the isoelectric point of each protein, where the net charge of protein was opposite to that of surfactant. However BSA was solubilized above pH 10, which is serveral pH units above the pI 4.9. The kinds of anions in aqueous phase influenced on protein solubilization while no significant trend was observed with different cations, Protein solubilization decreased with increase of the ion size in the order of F -, C1-, Br- and I -. The size of CTAB micelles did not change significantly with increasing ionic strength, but the solubilization decreased. Protein desolubilization showedropposite behaviors to the solubilization. Several model mixtures such as pepsin/ trypsin, pepsin/ribonuclease-a and BSAlribonucleaee-a were successfully separated from each other without changing enzymatic activities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.574-579
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• 2009

Acid- and pepsin-solubilized collagens were extracted from the skin of shark (Isurus oxyrinchus) and their physicochemical properties were characterized by amino acid analysis, SDS-PAGE, the composition of collagen types, solubility and denaturation temperature. Acid - and pepsin-solubilized collagens from shark skin had an imino acid of 188.8 and 186.2 residues/1,000 amino acids, respectively. SDS-PAGE showed two different${\alpha}$ chains ($\alpha1$ and $\alpha2$) and $\beta$-component. The component ratio of type I and V was 10:1, and the type III was not found. Solubility of acid-soluble collagen was low in the range of pH 6.0 to pH 11.0. On the other hand, pepsin-solubilized collagen showed a low solubility in the range of pH 7.0-9.0. Temperature for denaturation of acid- and pepsin-solubilized collagens were $25^{\circ}C$ and $27^{\circ}C$, respectively.

• Korean Journal of Veterinary Research
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• v.44 no.2
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• pp.269-277
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• 2004

Trichinella spiralis is one of the important zoonotic parasites with a wide variety of vertebrates hosts in nature. The purpose of this study were to analyze ESP(Excretory-Secretory Protein) antigen, to evaluate ELISA for the serological diagnosis of Trichinosis, and to survey T. spiralis infection in finishing pigs using the pepsin digestion method and ELISA in Korea. In the analysis of ESP antigen by SDS-PAGE and Western blot, 4 major bands (70, 55, 52.6, and 49 kDa) were revealed from the ESP antigen. Predilection sites of T. spiralis were the diaphragm, the tongue, masseter muscles, intercostal muscle, and hindlimb in orders in the experimentally infected rats. Sera from 581 swine were tested by ELISA with ESP antigen. The 54 (9.3%) sera were suspected as positive reactors, however, these 54 sera were determined as false positives by the use of Western blotting. This study demonstrated that the ELISA was not suitable for the examination of T. spiralis in pork. The diaphragm muscle samples of 251 finishing pigs were tested by the method of pepsin-digestion for the presence of Trichinella larvae, however, T. spiralis was not detected from the samples. We could not find out T. spiralis infection in pig in Korea pork.

• 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.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.14-19
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• 2014

This study investigated the effects of protease treatments (trypsin, chymotrypsin, and pepsin) under various pressure levels (0.1-300 MPa) for the characteristics of porcine placenta hydrolysates. According to gel electrophoretic patterns, the trypsin showed the best placental hydrolyzing activity followed by chymotrypsin, regardless of the pressure levels. In particular, the peptide bands of tryptic-digested hydrolysate were not shown regardless of applied pressure levels. The peptide bands of hydrolysate treated chymotrypsin showed gradual decreases in molecular weights ($M_w$) with increasing pressure levels. However, the pepsin did not show any evidences of placental hydrolysis even though the pressure levels were increased to 300 MPa. The gel permeation chromatography (GPC) profiles showed that the trypsin and pepsin had better placental hydrolyzing activities under high pressure (particularly at 200 MPa), with lower $M_w$ distributions of the hydrolysates. Pepsin also tend to lower the $M_w$ of peptides, while the major bands of hydrolysates being treated at 300 MPa were observed at more than 7,000 Da. There were some differences in amino acid compositions of the hydrolysates, nevertheless, the peptides were mainly composed of glycine (Gly), alanine (Ala), hydroxyproline (Hyp) and proline (Pro). Consequently, the results indicate that high pressure could enhance the placental hydrolyzing activities of the selected proteases and the optimum pressure levels at which the maximum protease activity is around 200 MPa.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.433-441
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• 1995

A series of experiments was conducted to determine the influence of various pepsin-HCL pretreatment factor, hereby the factors of duration of washing for the retrieved bags, inherent to the mobile nylon bag technique (MNBT), on apparent ileal digestibility of crude protein (AIDCP) and apparent ileal digestibility of dry matter (AIDDM). At last, the AIDCP and apparent ileal digestibility of amino acids (AIDAA) in maize, barley, wheat, rapeseed meal, cottonseed meal and three mixed diets were determined with the MNBT and ileo-rectal anastomis pigs (IRAT). For the MNBT techniques, bag measuring $25{\times}40$ MM and containing 0.75 g feedstuff samples, after pre-digestion in vitro, were introduced into the ileo-rectal anastomis pigs (IRAT) gastrointestinal tract through a duodenal cannula and recovered in the ileal digesta between 6 and 12 h. later. 1. The apparent ileal digestibility of dry matter (AIDDM) and crude protein (AIDCP) of the tested samples, with the exception of fish meal, determined by MNBT were not affected by the different pepsin-HCL pretreatment times in vitro between 2.5 h. and 4 h. 2. There was no significant (p > 0.05) difference of the AIDCP and AIDDM of maize determined by the MNBT among different pepsin concentration (0.03%, 0.07% and 0.1 %) treatment in vitro. 3. The AIDCP determined with the MNBT was affected by the washed and unwashed recovered bags from the ileal digesta. 4. The AIDCP and AID amino acids (AIDAA) of maize, barley, wheat, rapeseed meal, soya-bean meal, cottonseed meal and three mixed diets from the MNBT, with a solution of 0.01N HCL (PH 2) and 0.1% of pepsin concentration, a pepsin-HCL pretreatment time in vitro or 4h. and a washing time of the recovered bag from the ileal digesta compared well with those from the IRAT. The linear regression analysis showed a significant correlation (p < 0.01) of AIDCP and AIDDA between the IRAT and MNBT.

• Fisheries and Aquatic Sciences
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• v.24 no.12
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• pp.406-414
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• 2021

The objective of this study was to investigate the yield and characteristics of collagen protein extracted from the muscle of four different species of mantis shrimp: Miyakella nepa, Harpiosquilla harpax, Erugosquilla woodmasoni, and Odontodactylus cultrifer. Mantis shrimp muscle was extracted by using a pepsin-solubilization technique, with 0.5 M acetic acid and 5% pepsin enzyme. The highest collagen yield was from M. nepa muscle (0.478 ± 0.06%), which was significantly greater (p < 0.05) than that from H. harpax, O. cultrifer, and E. woodmasoni (0.313 ± 0.03%, 0.123 ± 0.02%, and 0.015 ± 0.00%, respectively). The freeze-dried collagen appeared as thin fibers, and formed an opaque film. The pepsin-soluble collagen (PSC) from four mantis shrimp species was analyzed by gel electrophoresis. The results showed that all species of mantis shrimp contained type I collagen, consisting of β, α1, and α2 subunits with average molecular weights of 250, 145, and 118 kDa, respectively. The study of the solubility of collagen showed that, for NaCl, collagen had the highest relative solubility in 2% NaCl (80.20 ± 4.95%). In contrast, the solubility decreased at higher NaCl concentrations. However, in terms of pH, collagen had the highest relative solubility at pH 3 (91.32 ± 5.14%), and its solubility decreased at higher pH. FT-IR spectroscopy was used to compare the collagen with a model compound. Five wavenumbers in the spectrum for model collagen were identified: Amide A (3,406-3,421 cm^-1), amide B (2,916-2,940 cm^-1), amide I (1,639-1,640 cm^-1), amide II (1,539-1,570 cm^-1), and amide III (1,234-1,250 cm^-1).

• Food Science and Biotechnology
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• v.15 no.2
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• pp.173-176
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• 2006

The effect of enzymatically hydrolyzed vital wheat gluten (EHG) on dough mixing and the baking quality of wheat flour frozen dough was examined. Three different proteases, pepsin, trypsin, and chymotrypsin, were tested individually, sequentially paired, or in combination of all three enzymes. Addition of 1% EHG produced no observable effect on the mixing properties of wheat flour dough. However, addition of 2.5% pepsin-hydrolyzed gluten decreased the mixing tolerance of the wheat flour, and 1% trypsin-hydrolyzed gluten increased the loaf volume of both frozen and non-frozen dough. This finding suggests that trypsin-hydrolyzed vital wheat gluten may serve as a baking additive in replacement for $KBrO_3$ to improve frozen dough quality.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.1
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• pp.45-51
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• 2009

In this study, food protein hydrolysates were prepared from six types of food protein: purified meat protein, whole egg protein, casein, isolated soy protein, concentrated rice protein, and gluten. Food proteins were hydrolyzed with pepsin and ethanol (80%)-soluble fractions of pepsin hydrolysates were employed for analysis. The products were colorless and odorless powders with low fat content and good solubility. The MW (molecular weight) of the protein hydrolysates was confirmed to be $200{\sim}1,800$ via gel filtration. Free amino acid contents accounted for less than 5% of the samples. The results of our amino acid analysis revealed that all food protein hydrolysates preserved their original amino acid compositions and nutritional values of their source proteins with highly pure oligopeptide mixtures. These results show that the food protein hydrolysates prepared in these investigations should prove excellent dietary nitrogen sources for a variety of applications.