Gibb W, Jeffery J
Biochem J. 1975 Mar;145(3):483-9. doi: 10.1042/bj1450483.
The retro steroids 17beta-hydroxy-5beta,9beta,10alpha-androstan-3-one and 5beta,9beta,10alpha-androstane-3,17-dione were good substrates for cortisone reductase in the presence of NADH, and the products corresponded to the respective 3beta-hydroxy compounds, in which the 3beta-hydroxyl group is axial and the absolute configuration is 3S. The analogous natural steroids 17beta-hydroxy-5beta,9alpha,10beta-androstan-3-one and 5beta,9alpha,10beta-androstane-3,17-dione were very poor substrates, and gave the corresponding 3alpha(equatorial,3R)-hydroxy compounds, and, in the latter case, also an appreciable amount of 3beta(axial, 3S)-hydroxy-5beta,9alpha,10beta-androstan-17-one. The natural steroids 17beta-hydroxy-5alpha,9alpha,10beta-androstan-3-one and 5alpha,9alpha,10beta-androstane-3,17-dione were better substrates than the retro steroid 17beta-hydroxy-5alpha,9beta,10alpha-androstan-3-one, but were not such good substrates as the retro steroids 17beta-hydroxy-5beta,9beta,10alpha-androstan-3-one and 5beta,9beta,10alpha-androstane-3,17-dione. Unlike these retro steroid 5beta,9beta,10alpha-androstan-3-ones, the natural steroids 17beta-hydroxy-5alpha,9alpha,10beta-androstan-3-one and 5alpha,9alpha,10beta-androstane-3,17-dione gave the corresponding 3alpha(axial,3R)-hydroxy compounds. The retro steroid 17beta-hydroxy-5alpha,9beta,10alpha-androstan-3-one was not a good substrate, and the product of reaction corresponded to the 3alpha(axial,3R)-hydroxy compound. The nature of substrate recognition by this enzyme is discussed in the light of these structure-activity relationships.
在烟酰胺腺嘌呤二核苷酸（NADH）存在的情况下，反式甾体17β-羟基-5β,9β,10α-雄甾烷-3-酮和5β,9β,10α-雄甾烷-3,17-二酮是可的松还原酶的良好底物，其产物对应于各自的3β-羟基化合物，其中3β-羟基为直立键，绝对构型为3S。类似的天然甾体17β-羟基-5β,9α,10β-雄甾烷-3-酮和5β,9α,10β-雄甾烷-3,17-二酮是非常差的底物，生成相应的3α（平伏键，3R）-羟基化合物，并且在后一种情况下，还生成相当数量的3β（直立键，3S）-羟基-5β,9α,10β-雄甾烷-17-酮。天然甾体17β-羟基-5α,9α,10β-雄甾烷-3-酮和5α,9α,10β-雄甾烷-3,17-二酮比反式甾体17β-羟基-5α,9β,10α-雄甾烷-3-酮是更好的底物，但不如反式甾体17β-羟基-5β,9β,10α-雄甾烷-3-酮和5β,9β,10α-雄甾烷-3,17-二酮那样是好的底物。与这些反式甾体5β,9β,10α-雄甾烷-3-酮不同，天然甾体17β-羟基-5α,9α,10β-雄甾烷-3-酮和5α,9α,10β-雄甾烷-3,17-二酮生成相应的3α（直立键，3R）-羟基化合物。反式甾体17β-羟基-5α,9β,10α-雄甾烷-3-酮不是好的底物，反应产物对应于3α（直立键，3R）-羟基化合物，并根据这些构效关系讨论了该酶对底物识别的性质。
