• Applied Biological Chemistry
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• v.43 no.4
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• pp.247-252
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• 2000

As functionality investigation of Korean traditional soybean fermentation foods, an antihypertensive peptide was separated during Chunggugjang fermentation by Bacillus subtilis CH-1023 and investigated inhibitory effect against angiotensin converting enzyme. After incubation at $20^{\circ}C,\;30^{\circ}C,\;40^{\circ}C,\;50^{\circ}C,\;60^{\circ}C$ for the $0{\sim}72$ hrs, protein content, protease activity and angiotensin converting enzyme inhibitory rate were determined. The protein content and protease activity were increased and reached maximum at 60 hrs fermentation with $40^{\circ}C$ and decreased after the 60 hrs fermentation. The optimum condition for antihypertensive peptide from Chunggugjang was appeared for 60 hrs at $40^{\circ}C$. Crude extract of Chunggugjang was partially purified by Amicon YM-3 membrane filtration and Sephadex G-10, G-25 gel filtration. The purified peptide showed inhibitory rate of 94.3% with 0.5 mg peptide content. The most prominent amino acid composition of the peptide from Chunggugjang was alanine, followed by phenylalanine, histidine.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1018-1023
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• 2007

Bacillus subtilis CH3-5 was isolated from cheonggukjang prepared according to traditional methods. CH3-5 secreted at least four different fibrinolytic proteases (63, 47, 29, and 20 kDa) into the culture medium. A fibrinolytic enzyme gene, aprE2, encoding a 29kDa enzyme was cloned from the genomic DNA of CH3-5, and the DNA sequence determined. aprE2 was overexpressed in heterologous B. subtilis strains deficient in extracellular proteases using a E. coli-Bacillus shuttle vector. A 29 kDa AprE2 band was observed and AprE2 seemed to exhibit higher activities towards fibrin rather than casein.