人胎盘17β-雌二醇脱氢酶与3-氯乙酰吡啶-腺嘌呤二核苷酸的烷基化反应

Alkylation of estradiol 17beta-dehydrogenase from human placenta with 3-chloroacetylpyridine--adenine dinucleotide.

作者信息

Biellmann J F, Branlant G, Nicolas J C, Pons M, Descomps B, Crastes de Paulet A

出版信息

Eur J Biochem. 1976 Apr 1;63(2):477-81. doi: 10.1111/j.1432-1033.1976.tb10250.x.

DOI:10.1111/j.1432-1033.1976.tb10250.x

Abstract

3-Chloroacetylpyridine--adenine dinucleotide, which is active as a hydride acceptor (Km = 0.6 mM), inactivates and alkylates estradiol 17beta-dehydrogenase. The kinetics of inactivation by 3-chloroacetylpyridine--adenine dinucleotide and the absence of inactivation by 3-chloroacetylpyridine ribose phosphate show that the alkylation follows the formation of a binary complex (Kd = 4.5 X 10(-4) M). Studies of the labelling by 3-chloro[2-14C]acetylpyridine--adenine dinucleotide and the rate of alkylation as a function of pH, give evidence to the alkylation of a cysteine, the stoichiometry being one mole per subunit. The 14C label is distributed between three chymotryptic peptides, one of which accounts for about 50% of the radioactive label.

摘要

3-氯乙酰吡啶-腺嘌呤二核苷酸作为氢化物受体具有活性（Km = 0.6 mM），它会使17β-雌二醇脱氢酶失活并烷基化。3-氯乙酰吡啶-腺嘌呤二核苷酸的失活动力学以及3-氯乙酰吡啶核糖磷酸酯不会导致失活这一情况表明，烷基化是在二元复合物形成之后发生的（Kd = 4.5×10⁻⁴ M）。对3-氯[2-¹⁴C]乙酰吡啶-腺嘌呤二核苷酸的标记研究以及烷基化速率随pH的变化情况，证明了半胱氨酸的烷基化，化学计量比为每个亚基一摩尔。¹⁴C标记分布在三种胰凝乳蛋白酶肽段之间，其中一种约占放射性标记的50%。