α,β-elimination reaction of O-acetylserine sulfhydrylase.: Is the pyridine ring required?
α,β-elimination reaction of O-acetylserine sulfhydrylase.: Is the pyridine ring required?
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DOI：
10.1016/s1570-9639(03)00052-9
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发表时间：
2003-04-11
影响因子：
3.2
通讯作者：
Cook, PF
中科院分区：
文献类型：
--
作者：
Cook, PF
O-乙酰丝氨酸硫化氢解酶（OASS）催化O-乙酰-L-丝氨酸（OAS）中乙酸的消除，然后加入二硫化物以产生L-半胱氨酸。定点诱变已被用来取代活性位点丝氨酸，S272，形成氢键的吡哆醛5-磷酸（PLP）与丙氨酸和天冬氨酸的N1。基于紫外-可见光谱和稳态动力学研究，这两种突变酶催化消除反应的效率等于野生型酶。数据与针对消除反应提出的抗E-2反应一致。(C)2003 Elsevier Science B. V.保留所有权利。
O-Acetylserine sulfhydrylase (OASS) catalyzes the elimination of acetate from O-acetyl-L-serine (OAS) followed by addition of bisulfide to give L-cysteine. Site-directed mutagenesis has been used to replace the active site serine, S272, which forms a hydrogen bond to N1 of pyridoxal 5-phosphate (PLP) with alanine and aspartate. Based on UV-visible spectral and steady-state kinetic studies, both mutant enzymes catalyze the elimination reaction with an efficiency equal to that of the wild-type enzyme. Data are consistent with an anti-E-2 reaction proposed for the elimination reaction. (C) 2003 Elsevier Science B.V. All rights reserved.