A SINGLE AMINO-ACID SUBSTITUTION IN LACTATE-DEHYDROGENASE IMPROVES THE CATALYTIC EFFICIENCY WITH AN ALTERNATIVE COENZYME
A SINGLE AMINO-ACID SUBSTITUTION IN LACTATE-DEHYDROGENASE IMPROVES THE CATALYTIC EFFICIENCY WITH AN ALTERNATIVE COENZYME
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DOI：
10.1016/0006-291x(90)90861-g
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发表时间：
1990-01-30
影响因子：
3.1
通讯作者：
HOLBROOK, JJ
中科院分区：
文献类型：
--
作者：
FEENEY, R;CLARKE, AR;HOLBROOK, JJ
利用定点突变，嗜热脂肪芽孢杆菌NADH连接的乳酸脱氢酶在单个残基上发生部分改变，转变为对NADPH的辅酶专一性。唯一的变化是在氨基酸序列的第53位，保守的天冬氨酸被丝氨酸取代。这种取代是为了减少空间位阻对NADPH的额外磷酸基团的结合，并消除天冬氨酸基团的负电荷。得到的突变酶的催化效率是含有NADPH的野生型酶的20倍。
Using site-directed mutagenesis, the NADH-linked lactate dehydrogenase from Bacillus stearothermophilus has been partially altered at a single residue to shift to coenzyme specificity towards NADPH. The single change is at position 53 in the amino acid sequence where a conserved aspartate has been replaced by a serine. This substitution was made to reduce steric hindrance on binding of the extra phosphate group of NADPH and to remove the negative charge of the aspartate group. The resultant mutant enzyme is 20 times more catalytically efficient than the wild-type enzyme with NADPH.