Study of 3 alpha, 20 beta-hydroxysteroid dehydrogenase with an enzyme-generated affinity alkylator: dual enzyme activity at a single active site.
Study of 3 alpha, 20 beta-hydroxysteroid dehydrogenase with an enzyme-generated affinity alkylator: dual enzyme activity at a single active site.
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使用酶生成的亲和烷基化剂研究 3 α、20 β-羟基类固醇脱氢酶：单个活性位点的双酶活性。
DOI：
10.1021/bi00563a002
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发表时间：
1980
期刊：
影响因子：
2.9
通讯作者：
Tobias,B
中科院分区：
文献类型：
--
作者：
Strickler,RC;Covey,DF;Tobias,B
Ronald C. Strickler,** Douglas F. Covey和Brian Tobias摘要：合成了底物17/3-[(1 S')-1-羟基-2-丙基]-androst-4-en-3-one （/3-HPA）及其酶生成的al- kyylation产物17/3-（1-氧-2-丙基）androst-4-en-3-one (OPA)，研究了市售可的松还原酶（EC 1.1）中3a和20/3活性的关系。1.53)来自氢链霉菌。/3-HPA，衬底[表观Km= 145µ；Fmax= 63 nmol （minµg）“1]，当可的松还原酶将其酶氧化为OPA时，根据准一级动力学以时间依赖性和不可逆的方式同时失活3a和20/3活性。OPA是一种亲和的烷基化类固醇（Ki= 40.5µ；fc3= 1.8 X 10 ' 2 s ' 1），可以同时以时间依赖性和不可逆的方式失活3a和20/3活性。pH为7时，β -(10 h)或OPA （41 min）酶失活的f1/2比pH为9.2时（/3-HPA, 16 min， OPA, 3.3 min）慢。底物（孕酮，20/3-羟基孕酮，5 -二氢睾酮），但不是所有类固醇（20a- a4 -孕酮和17/3-雌二醇），保护酶活性免受/3-HPA和OPA的损失。HPA的a异构体不会被酶氧化，因此不会导致3a或20/3活性的失活。因此，/3-HPA作为酶促生成可的松还原酶的强亲和烷基化物的底物。其次，在所有实验条件下3a和20/3活性的相同变化显然是由单个酶活性位点的双酶活性引起的。20/3-羟基类固醇脱氢酶（20/3-HSD）1.53;平凡的名字，可的松还原酶)被正式命名为20-酮生成素类固醇的特异性。Pocklington和Jeffrey（1968）观察到与3-酮-雄甾烷类固醇的反应，并在密苏里州圣路易斯华盛顿大学医学院妇产科和药学系发表了几篇关于3-氧化-f的报告
Ronald C. Strickler,** Douglas F. Covey, and Brian Tobias abstract: The substrate 17/3-[(1 S')-1-hydroxy-2-propynyl]-androst-4-en-3-one (/3-HPA) and its enzyme-generated al-kylating product 17/3-(1-oxo-2-propynyl) androst-4-en-3-one (OPA) were synthesized to investigate the relationship between the 3a and 20/3 activities observed in commercially available cortisone reductase (EC 1.1. 1.53) from Streptomyces hydro-genans./3-HPA, a substrate [apparent Km= 145 µ; Fmax= 63 nmol (min µg)" 1], when enzymatically oxidized by cortisone reductase to OPA, inactivates simultaneously the 3a and 20/3 activities in a time-dependent and irreversible manner following pseudo-first-order kinetics. OPA alone, an affinity alkylating steroid (Ki= 40.5 µ; fc3= 1.8 X 10" 2 s" 1), si-multaneously inactivates 3 a and 20/3 activities in a time-de-pendent and irreversible manner. At pH 7, the f1/2 of enzyme inactivation for ß-(10 h) or OPA (41 min) is slower than at pH 9.2 (/3-HPA, 16 min, and OPA, 3.3 min). Substrates (progesterone, 20/3-hydroxypregn-4-en-3-one, and 5a-di-hydrotestosterone), but not all steroids (20a-A4-pregn-4-en-3-one and 17/3-estradiol), protect against loss of both enzyme activities by/3-HPA and OPA. The a isomer of HPA is not enzymatically oxidized and therefore does not cause inacti-vation of either 3a or 20/3 activity. Thus,/3-HPA functions as a substrate for the enzymatic generation of a powerful affinity alkylator of cortisone reductase. Second, the identical change in both the 3a and 20/3 activities in all experimental conditions clearly results from dual enzyme activity at a single enzyme active site. e oxidoreductase 20/3-hydroxysteroid dehydrogenase (20/3-HSD)(EC 1.1. 1.53; trivial name, cortisone reductase) is officially named as specific for 20-ketopregnene steroids. Pocklington & Jeffrey (1968) observed reaction with 3-keto-androstane steroids and initiated several reports of 3-oxido-f From the Departments of Obstetrics and Gynecology and Pharma-cology, Washington University School of Medicine, St. Louis, Missouri