A MUTANT ALPHA-AMYLASE WITH ENHANCED ACTIVITY SPECIFIC FOR SHORT SUBSTRATES

被引：15
|
作者：
MATSUI, I [1 ]
ISHIKAWA, K [1 ]
MIYAIRI, S [1 ]
FUKUI, S [1 ]
HONDA, K [1 ]
机构：
[1] FUKUYAMA UNIV,DEPT ENGN,FUKUYAMA,HIROSHIMA 72902,JAPAN
来源：
FEBS LETTERS | 1992年 / 310卷 / 03期
关键词：
ALPHA-AMYLASE; SUBSITE AFFINITY; SITE-DIRECTED MUTAGENESIS; MALTOOLIGOSACCHARIDE; SACCHAROMYCOPSIS;
D O I：
10.1016/0014-5793(92)81335-J
中图分类号：
Q5 [生物化学]; Q7 [分子生物学];
学科分类号：
071010 ; 081704 ;
摘要：
The 210th lysine (K210) at the active site in Saccharomycopsis fibuligera alpha-amylase was altered to arginine (R) or asparagine (N) by site-directed mutagenesis. Replacement of K210 by R strengthened the 7th and weakened the 8th subsite affinities. K210 was found to contribute to both the 8th and the 7th subsites. The catalytic activity of the K210R enzyme for the hydrolysis of maltose (G2) was three-times higher than that of the native enzyme due to an increase in the affinity of the 7th subsite adjacent to the catalytic site, whereas the activity of the K210N enzyme for G2 was decreased to 1% of that of the native enzyme by a reduction in the 7th subsite affinity.
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页码：216 / 218
页数：3
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