Hastings C D, Brekke I, Purvis K, Attramadal A, Hansson V
Endocrinology. 1980 Dec;107(6):1762-6. doi: 10.1210/endo-107-6-1762.
The present paper demonstrates the presence of at least two 3-hydroxysteroid oxidoreductases (3-HSO) in rat testis, prostate, and epididymis cytosol preparations. The enzymes were either NADH or NDAPH dependent. Further investigation by Sephadex G-200 chromatogrphy revealed the presence of enzyme activities in the void volume (peak 1) and also eluting close to the methyl-carbonic anhydrase standard (mol wt, 34,000; peak 2). Enzyme activity in peak 1 was predominantly stimulated by NADH and that in peak 2 was stimulated mainly by NADPH. Both 3 alpha- and 3 beta-HSO activities were observed in testicular eluates from 1; 3 beta-Adiol accounted for up to 50% of the 5 alpha-androstanediols formed. In peak 2,3 alpha-HSO constituted more than 90% of the enzyme activity. In contrast, the prostatic and epididymal eluates revealed only 3 alpha-HSO activity; 3 beta-Adiol constituted less than 5% of the 5 alpha-androstanediols formed in either peak 1 or 2. The apparent Km values for enzyme activation reveal differences in sensitivity to cofactors for enzymes in peaks 1 and 2 and also among testis, epididymis, and prostate. NADH caused a very similar activation of enzyme activity in peak 1 or the prostate and epididymis (Km 50-100 micro M), whereas the enzyme in the testis was activated by much lower cofactor concentration (Km approximately 5 microM). It is possible that this enzyme activity may represent microsomal contamination. The enzyme activity in peak 2 revealed very similar sensitivity to NADPH in all three organs (Km, 0.6-1.7 microM), confirming previous studies from our laboratory that the soluble. NADPH-dependent enzymes in all three tissues are very similar, if not identical.
本文证明在大鼠睾丸、前列腺和附睾胞质溶胶制剂中至少存在两种3-羟基类固醇氧化还原酶（3-HSO）。这些酶依赖于NADH或NADPH。通过葡聚糖G-200色谱进一步研究发现，在空体积（峰1）中存在酶活性，并且在接近甲基碳酸酐酶标准物（分子量34,000；峰2）处也有洗脱。峰1中的酶活性主要受NADH刺激，峰2中的酶活性主要受NADPH刺激。在1的睾丸洗脱物中观察到3α-和3β-HSO活性；3β-雄甾二醇占形成的5α-雄甾二醇的50%。在峰2中，3α-HSO占酶活性的90%以上。相比之下，前列腺和附睾洗脱物仅显示3α-HSO活性；3β-雄甾二醇在峰1或峰2中形成的5α-雄甾二醇中占不到5%。酶激活的表观Km值揭示了峰1和峰2中的酶以及睾丸、附睾和前列腺中对辅因子敏感性的差异。NADH在峰1或前列腺和附睾中引起非常相似的酶活性激活（Km为50 - 100μM），而睾丸中的酶被低得多的辅因子浓度激活（Km约为5μM）。这种酶活性可能代表微粒体污染。峰2中的酶活性在所有三个器官中对NADPH显示出非常相似的敏感性（Km为0.6 - 1.7μM），证实了我们实验室先前的研究，即所有三个组织中的可溶性NADPH依赖性酶即使不完全相同也非常相似。
