STEREOCHEMISTRY OF CONVERSION OF THE SUICIDE SUBSTRATES BETA-CHLORO-D-ALANINE AND D-SERINE AND L-SERINE O-SULFATES INTO PYRUVATE BY D-AMINO-ACID AMINOTRANSFERASE AND BY L-ASPARTATE AMINOTRANSFERASE
STEREOCHEMISTRY OF CONVERSION OF THE SUICIDE SUBSTRATES BETA-CHLORO-D-ALANINE AND D-SERINE AND L-SERINE O-SULFATES INTO PYRUVATE BY D-AMINO-ACID AMINOTRANSFERASE AND BY L-ASPARTATE AMINOTRANSFERASE
复制标题
DOI：
10.1039/p19940002137
复制
发表时间：
1994-08-07
期刊：
影响因子：
--
通讯作者：
YOUNG, DW
中科院分区：
文献类型：
--
作者：
AXELSSON, BS;FLOSS, HG;YOUNG, DW
D-氨基酸氨基转移酶催化β-氯-D-丙氨酸和D-丝氨酸O-硫酸盐转化为氨基丙烯酸酯中间体。这要么与磷酸吡哆醛反应，形成酶的反应性抑制剂，要么质子化和水解得到丙酮酸。质子化反应以适度的立体选择性发生。表明在用氢取代离开基团时，总体上保留了立体化学。L-丝氨酸O-硫酸盐与L-天冬氨酸氨基转移酶的对应反应具有很低的立体选择性或没有立体选择性。
beta-Chloro-D-alanine and D-serine O-sulfate are converted into a putative aminoacrylate intermediate by D-amino acid aminotransferase. This either reacts with pyridoxal phosphate to form a reactive inhibitor of the enzyme or it is protonated and hydrolysed to give pyruvate. The protonation reaction is shown to occur with modest stereoselectivity. indicating overall retention of stereochemistry in replacement of the leaving group by hydrogen. The corresponding reaction of L-serine O-sulfate using L-aspartate aminotransferase shows little or no stereoselectivity.