Ryan R A, Carrol J
Biochim Biophys Acta. 1976 Apr 8;429(2):391-401. doi: 10.1016/0005-2744(76)90287-4.
A steroid sulphotransferase (EC 2.8.2.2) was partially purified from female rat liver. The enzyme was active towards the substrates, dehydroepiandrosterone, epiandrosterone and pregnenolone but was inactive towards oestrogens, cholesterol and ergocalciferol. A pH optimum of 5.0 was recorded but the enzyme was unstable at low pH. The enzyme was stimulated slightly by the addition of reducing agents and inhibited by p-chloromercuribenzoate and HgCl2. Crude enzyme activity was markedly stimulated by divalent cations but this effect was not observed with purified enzyme. A Km of 13 muM was calculated for the donor substrate 3'-phosphoadenylyl sulphate and the acceptor substrate, dehydroepiandrosterone had a Km value of 6 muM. The enzyme appeared to be highly susceptible to product inhibition by adenosine 3', 5'-diphosphate.
从雌性大鼠肝脏中部分纯化出一种类固醇硫酸转移酶（EC 2.8.2.2）。该酶对底物脱氢表雄酮、表雄酮和孕烯醇酮具有活性，但对雌激素、胆固醇和麦角钙化醇无活性。记录到的最适pH值为5.0，但该酶在低pH值下不稳定。添加还原剂会对该酶有轻微刺激作用，而对氯汞苯甲酸和氯化汞会抑制该酶。粗酶活性受到二价阳离子的显著刺激，但纯化后的酶未观察到这种效应。计算得出供体底物3'-磷酸腺苷硫酸酯的Km值为13μM，受体底物脱氢表雄酮的Km值为6μM。该酶似乎对3',5'-二磷酸腺苷的产物抑制高度敏感。
