Acetylation of S-substituted cysteines by a rat liver and kidney microsomal N-acetyltransferase.
Acetylation of S-substituted cysteines by a rat liver and kidney microsomal N-acetyltransferase.
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大鼠肝脏和肾脏微粒体 N-乙酰转移酶对 S-取代半胱氨酸进行乙酰化。
DOI：
10.1042/bj1470283
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
J. Elce
中科院分区：
文献类型：
--
作者：
R. M. Green;J. Elce
1.通过使用涉及与S-苄基-L-半胱氨酸和[1 - 14 C]乙酰辅酶A孵育并用乙酸乙酯提取放射性产物的测定，研究了大鼠肝脏和肾脏制剂中的乙酰辅酶A-S-取代的半胱氨酸N-乙酰转移酶。2.该酶与微粒体组分结合，不能溶解。金属离子、EDTA和洗涤剂对酶活性无明显影响。对氯汞苯甲酸盐和N-乙基马来酰亚胺抑制该酶。3.其他S-取代的半胱氨酸以与S-苄基-L-半胱氨酸大致相同的速率被乙酰化。可以检测到半胱氨酸本身以及甲硫氨酸、乙硫氨酸和色氨酸的乙酰化，但要慢得多。天冬氨酸、甘氨酸、苯丙氨酸和丝氨酸的乙酰化未检测到。棕榈酰辅酶A不是底物。4.该酶可能负责巯基尿酸合成的乙酰化步骤;除了该酶可能参与在某些氨基酸代谢紊乱中发生量升高的那些氨基酸的乙酰化之外，尚不知道更多的生理功能。
1. An acetyl-CoA--S-substituted cysteine N-acetyltransferase in rat liver and kidney preparations was investigated, by using an assay involving incubations with S-benzyl-L-cysteine and [l-14C]acetyl-CoA and extraction of the radioactive product with ethyl acetate. 2. The enzyme was associated with the microsomal fraction and could not be solubilized. Metal ions, EDTA and detergents did not significantly affect the enzyme activity. p-Chloromercuribenzoate and N-ethylmaleimide inhibited the enzyme. 3. Other S-substituted cysteines were acetylated at about the same rate as S-benzyl-L-cysteine. Acetylation of cysteine itself and of methionine, ethionine and tryptophan could be detected but was much slower. Acetylation of aspartic acid, glycine, phenylalanine and serine could not be detected. Palmitoyl-CoA was not a substrate. 4. The enzyme is presumably responsible for the acetylation step of mercapturic acid synthesis; a more physiological function is not yet known, except that the enzyme may be involved in acetylation of those amino acids which occur in elevated amounts in some disorders of amino acid metabolism.