Cénas N K, Marcinkeviciene J A, Kulys J J, Usanov S A
Institute of Biochemistry, Lithuanian Academy of Sciences, Vilnius, USSR.
FEBS Lett. 1990 Jan 1;259(2):338-40. doi: 10.1016/0014-5793(90)80042-h.
Adrenodoxin stimulated the oxidation of NADPH by 1,4-benzoquinone, catalyzed by NADPH:adrenodoxin reductase. It prevented the enzyme inhibition by NADPH and formed an additional pathway of benzoquinone reduction presumably via reduced adrenodoxin. In the presence of 100-400 microM NADP+, which increased the Km of NADPH, adrenodoxin acted as a partial competitive inhibitor for NADPH decreasing its TN/Km by a limiting factor of 3. Ki of adrenodoxin decreased on the NADP+ concentration decrease and was estimated to be about 10(-8) M in the absence of NADP+.
肾上腺皮质铁氧化还原蛋白通过NADPH：肾上腺皮质铁氧化还原蛋白还原酶催化，刺激1,4 - 苯醌氧化NADPH。它可防止NADPH对该酶的抑制作用，并可能通过还原型肾上腺皮质铁氧化还原蛋白形成苯醌还原的额外途径。在100 - 400微摩尔NADP⁺存在下，NADP⁺增加了NADPH的米氏常数（Km），肾上腺皮质铁氧化还原蛋白作为NADPH的部分竞争性抑制剂，使其转数/米氏常数（TN/Km）降低了3倍的限制因子。随着NADP⁺浓度降低，肾上腺皮质铁氧化还原蛋白的抑制常数（Ki）减小，在无NADP⁺时估计约为10⁻⁸ M。
