Wiener M
Mech Ageing Dev. 1978 Jun;7(6):433-44.
Two substances which affect the activity and kinetic characteristics of 3 beta-hydroxy-delta 5-steroid dehydrogenase (delta 5-3 beta-HSD) have been recovered from homogenates of term human placenta by extraction with organic solvents after ethanol precipitation of protein. One of these substances, an inhibitor of the enzyme, is a non-polar unstable substance, which dialyzes through a cellulose nitrate membrane and which appears to be present in the tissue both in the free state and bound to either the enzyme or the microsomal membrane. It was not possible to produce a delta 5-3 beta-HSD preparation free of the inhibitor. The other substance is an activator, polar and stable with a molecular weight of less then 500, which increases both the apparent Km and the apparent V max of delta 5-3 beta-HSD. It is postulated that both substances play a part in control of placental progesterone synthesis.
通过对人足月胎盘匀浆进行乙醇沉淀蛋白质后用有机溶剂萃取，已从其中分离出两种影响3β-羟基-δ5-甾体脱氢酶（δ5-3β-HSD）活性及动力学特性的物质。其中一种物质是该酶的抑制剂，为非极性不稳定物质，可透过硝酸纤维素膜进行透析，且似乎在组织中以游离状态存在，同时也与酶或微粒体膜结合。无法制备出不含该抑制剂的δ5-3β-HSD制剂。另一种物质是激活剂，具有极性且稳定，分子量小于500，它可同时增加δ5-3β-HSD的表观Km值和表观Vmax值。据推测，这两种物质在胎盘孕酮合成的调控中均发挥作用。
