Bollenbacher W E, Faux A F, Galbraith M N, Gilbert L I, Horn D H, Wilkie J S
Steroids. 1979 Nov;34(5):509-26. doi: 10.1016/s0039-128x(79)80013-6.
3 beta, 14 alpha-Dihydroxy-5 alpha-7-en-6-one (5 alpha-ketodiol) (1) is metabolized by the prothoracic glands to 2,22-dideoxy-5 alpha-ecdysone (4) and 2-deoxy-5 alpha-ecdysone (3) but not to ecdysone (5) or any other 5 beta-metabolites. Similarly, 3 beta,5 alpha,14 alpha-trihydroxy-cholest-7-en-6-one (5 alpha-ketotriol) (8) is hydroxylated at C-22 and C-25 (9,10) of the side chain. However, 3 beta,14 alhpa-dihydroxy-cholesta-4,7-diene-6-one (ketodienediol) (11) is not metabolized. The absence of 2 beta-hydroxymetabolites for substrates (1) and (8) implies that hydroxylation at C-2 can occur only when the A-B rings are cis fused (5 beta-configuration). By contrast, the enzyme complexes that introduce hydroxyls at C-22 and C-25 do not exhibit a preference for cis over trans fusion and appraently cannot recognize the planar A-B ring configuration.
3β,14α-二羟基-5α-胆甾-7-烯-6-酮（5α-酮二醇）（1）被前胸腺代谢为2,22-二脱氧-5α-蜕皮激素（4）和2-脱氧-5α-蜕皮激素（3），但不会代谢为蜕皮激素（5）或任何其他5β-代谢产物。同样，3β,5α,14α-三羟基胆甾-7-烯-6-酮（5α-酮三醇）（8）在侧链的C-22和C-25位（9,10）发生羟基化。然而，3β,14α-二羟基胆甾-4,7-二烯-6-酮（酮二烯二醇）（11）不被代谢。底物（1）和（8）不存在2β-羟基代谢产物，这意味着只有当A-B环为顺式稠合（5β-构型）时，C-2位才会发生羟基化。相比之下，在C-22和C-25位引入羟基的酶复合物对顺式稠合和反式稠合没有偏好，显然无法识别平面A-B环构型。
