A New Family of<scp>D</scp>-2-Hydroxyacid Dehydrogenases That Comprises<scp>D</scp>-Mandelate Dehydrogenases and 2-Ketopantoate Reductases
作者:Yusuke WADA、Saho IWAI、Yusuke TAMURA、Tomonori ANDO、Takeshi SHINODA、Kazuhito ARAI、Hayao TAGUCHI
DOI:10.1271/bbb.70827
日期:2008.4.23
The gene for the d-mandelate dehydrogenase (d-ManDH) of Enterococcus faecalis IAM10071 was isolated by means of an activity staining procedure and PCR and expressed in Escherichia coli cells. The recombinant enzyme exhibited high catalytic activity toward various 2-ketoacid substrates with bulky hydrophobic side chains, particularly C3-branched substrates such as benzoylformate and 2-ketoisovalerate, and strict coenzyme specificity for NADH and NAD+. It showed marked sequence similarity with known NADP-dependent 2-ketopantoate reductases (KPR). These results indicate that together with KPR, d-ManDH constitutes a new family of d-2-hydroxyacid dehydrogenases that act on C3-branched 2-ketoacid substrates with various specificities for coenzymes and substrates.
通过活性染色程序和PCR分离粪肠球菌IAM10071的d-扁桃酸脱氢酶(d-ManDH)基因,并在大肠杆菌细胞中表达。该重组酶对各种具有大量疏水侧链的2-酮酸底物,特别是C3支链底物,如苯甲酰甲酸和2-酮异戊酸,表现出高催化活性,并对NADH和NAD+表现出严格的辅酶特异性。它与已知的 NADP 依赖性 2-酮泛解酸还原酶 (KPR) 显示出显着的序列相似性。这些结果表明,d-ManDH 与 KPR 一起构成了一个新的 d-2-羟基酸脱氢酶家族,其作用于 C3 支链 2-酮酸底物,对辅酶和底物具有各种特异性。