Motosugi K, Esaki N, Soda K
J Bacteriol. 1982 May;150(2):522-7. doi: 10.1128/jb.150.2.522-527.1982.
A new enzyme, DL-2-haloacid dehalogenase, was isolated and purified to homogeneity from the cells of Pseudomonas sp. strain 113. This enzyme catalyzed non-stereospecific dehalogenation of both of the optical isomers of 2-chloropropionate through an SN2 type of reaction; L- and D-lactates were formed from D- and L-2-chloropropionates, respectively. The enzyme acted on 2-halogenated aliphatic carboxylic acids whose carbon chain lengths were less than five. It also dehalogenated trichloroacetate to form oxalate and showed maximum activity at pH 9.5. The Michaelis constants for substrates were as follows: 5.0 mM for monochloroacetate, 1.1 mM for L-2-chloropropionate, and 4.8 mM for D-2-chloropropionate. DL-2-Haloacid dehalogenase was inhibited by HgCl2, ZnSO4, and MnSO4, but was not affected by thiol reagents, such as p-chloromercuribenzoate and iodoacetamide. This enzyme had a molecular weight of about 68,000 and appeared to be composed of two subunits identical in molecular weight.
一种新的酶，DL-2-卤代酸脱卤酶，从假单胞菌属菌株113的细胞中分离并纯化至同质。这种酶通过SN2型反应催化2-氯丙酸的两种光学异构体的非立体特异性脱卤；分别由D-和L-2-氯丙酸形成L-和D-乳酸。该酶作用于碳链长度小于5的2-卤代脂肪族羧酸。它还能使三氯乙酸脱卤形成草酸盐，并且在pH 9.5时表现出最大活性。底物的米氏常数如下：一氯乙酸为5.0 mM，L-2-氯丙酸为1.1 mM，D-2-氯丙酸为4.8 mM。DL-2-卤代酸脱卤酶受到HgCl2、ZnSO4和MnSO4的抑制，但不受对氯汞苯甲酸和碘乙酰胺等硫醇试剂的影响。这种酶的分子量约为68,000，似乎由两个分子量相同的亚基组成。
