| Autor: |
Tsuchida, Osamu, Yamagata, Yohei, Ishizuka, Takehiko, Arai, Teruyoshi, Yamada, Jun-Ichi, Takeuchi, Michio, Ichishima, Eiji |
| Zdroj: |
Current Microbiology; Jan1986, Vol. 14 Issue 1, p7-12, 6p |
| Abstrakt: |
An alkaline serine proteinase was purfied from the culture broth of an alkalophilic Bacillus sp. NKS-21. The molecular weight was estimated to be 22,000 by a gel filtration method and 31,000 by SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to be 8.2. The amino acid composition and CD spectrum were determined. The alkaline proteinase had a pH optimum at 10-11 for milk casein digestion. The specific activity of the alkaline proteinase was 0.35 katal/kg of protein at pH 10.0 for milk casein hydrolysis. The substrate specificity of the alkaline proteinase was studied by using the oxidized, insulin B-chain and angiotensin. An initial cleavage site was observed at Leu-Tyr, secondary site at Leu-Val, and additional sites at Gln-His, Tyr-Thr, and Asn-Gln in the oxidized insulin B-chain at pH 10.0. In comparison with the subtilisins Carlsberg and Novo, the alkaline proteinase from Bacillus sp. showed a unique specificity toward the oxidized insulin B-chain. Hydrolysis of angiotensin at pH 10.0 with the alkaline proteinase was observed at Tyr-Ile. The proteinase has a K of 0.1 m M and k of 3.3 s with angiotensin as substrate. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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