• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.417-424
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• 2003

Inhibitory activities against angiotensin I-converting enzyme (ACE) of enzymatic hydrolysates of porcine skeletal muscle proteins were investigated. Myosin B, myosin, actin, tropomyosin, troponin and water-soluble proteins extracted from pork loin were digested by eight kinds of proteases, including pepsin, $\alpha$-chymotrypsin, and trypsin. After digestion, hydrolysates produced from all proteins showed ACE inhibitory activities, and the peptic hydrolysate showed the strongest activity. In the case of myosin B, the molar concentration of peptic hydrolysate required to inhibit 50% of the activity increased gradually as digestion proceeded. The hydrolysates produced by sequential digestion with pepsin and $\alpha$-chymotrypsin, pepsin and trypsin or pepsin and pancreatin showed weaker activities than those by pepsin alone, suggesting that ACE inhibitory peptides from peptic digestion might lose their active sequences after digestion by the second protease. However, the hydrolysates produced by sequential digestion showed stronger activities than those by $\alpha$-chymotrypsin, trypsin or pancreatin alone. These results suggested that the hydrolysates of porcine meat were able to show ACE inhibitory activity, even if they were digested in vivo, and that pork might be a useful source of physiologically functional factors.

• The Korean Journal of Food And Nutrition
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• v.15 no.4
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• pp.364-369
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• 2002

Streptomyces shows a eukaryotic characteristic that vegetative cell can grow into mycelial form and has morphological and physiological differentiation at a certain period during its life cycle. Streptomyces has been used for the production of many biologically active compounds, such as antibiotics and pronase. Production of second metabolites and differentiation of the vegetative cell share the certain period of its lift cycle. Therefore, second metabolites may affect the differentiation of the vegetative cell. One of the microbial hormone, called A-factor, regulates the production of second metabolites, sporulation and differentiation of the cells. Streptomyces griseus produces streptomycin as well as many different kinds of proteinase. As mentioned, period of proteinases production overlaps with the period of differentiation of the vegetative cells. Protease may play a important role for the differentiation of the cells. In this paper, function of the SGPD gene cloned from S. griseus IFO 13350 tested whether it affects for the differentiation of A-factor mutated S. griseus HH1 and S. griseus IFO13350. pWHM3 and pWHM3-sprD plasmid was transformed into S. griseus HH1 and S. griseus IFO13350. Chymotrypsin activity of the cultured medium of the transformants with pWHM3-sprD plasmid didn't show any change with that of the transformants with plasmid only. The transformants with pWHM3-sprD plasmid didn't show the increase of the production of actinorhodin as well as morphological change in S. griseus IFO 13350 and HH1, as well. The promoter sequences of the SGPA and SGPB gene which encode chymotrypsin-like protease, were compared with that of SGPD gene. Regulatory mechanism of gene expression of proteinase genes will be studied for the development of high production system for protease as well as the function of the proteases.

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.163.2-163
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• 1994

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.299.1-299
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• 1995

No Abstract, See Full Text

• Bulletin of the Korean Chemical Society
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• v.17 no.10
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• pp.967-969
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• 1996

• 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 Microbiology and Biotechnology
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• v.2 no.1
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• pp.1-6
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• 1992

The aspartame, $\alpha$-L-aspartyl-L-phenylalanine methylester, is an artificial sweetener. Taking advantage of the fact that the aspartame is a derivative of dipeptide, synthesis of aspartame from the artificial polypeptide made by an artificial gene has been attempted. The artificial polypeptide (LAP32), a polymer of tripeptide (aspartyl-phenylalanyl-lysine), was purified from the E. coli cells harboring a recombinant plasmid containing the artificial gene. This polypeptide was then digested with trypsin and carboxypeptidase B to produce dipeptide (Asp-Phe). Using the esterase activity of $\alpha$-chymotrypsin, the dipeptide was directly converted into Asp-Phe methylester in a water-methanol system. When the methanol concentration in reaction mixture was 25%, 50% of dipeptide was converted to the dipeptide methylester without producing any by-products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.438-443
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• 1999

A livetin solution(LS) containing yolk immunoglobulins(IgY) was separated by treating the egg yolk with natural gum, carrageenan. Carrageenan has been used as a food ingredient. Relative absorbance of IgY LS after proteolysis was investigated. IgY LS was fairly stable to pepsin digestion at pH 3.0. However, IgY LS appeared to be susceptible to pepsin digestion at pH 2.0, showing 18% of relative absorbance and complete breakdown H chain after 30 min exposure. Relative absorbance of IgY LS was considerably high after exposure to trypsin and chymotrypsin for 8 hr. IgY LS showed especially good stability to chymotrypsin digestion.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.329-332
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• 2013

In present preliminary report, we showed the possibility of silk sericin (SS) in enzyme immobilization. SS beads were prepared and enzymes were immobilized on it. The specific activity of immobilized a-chymotrypsin retained more than 87% compared to the free enzyme. The immobilized a-chymotrypsin has better stability against ethanol especially those immobilized on SS beads coagulated in methanol. Immobilized trypsin and lipase had also comparable apparent activity compared to free enzyme. Our result indicates that SS could be a good candidate for enzyme immobilization support due to its hydrophilicity.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.264-267
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• 1990

The objectives of the current studies were to establish the optimal conditions for the production of extracellular protease inhibitor in a strain of Streptomyces fradiae. As results, it was found that cell specific growth rate was very critical for the production of protease inhibitor and the optimum specific growth rate was found to be 0.05 h$^{-1}$ . Dissolved oxygen tension and pH were also important to regulate the inhibitor production. The inhibitory mode of the purified inhibitor to .alpha.-chymotrypsin was found to be competitive (K$_{i}$=5.5*10$^{-7}$ M). One mole of inhibitor could bind two moles of .alpha.-chymotrypsin and the complex has very low dissociation constant.t.