Fang X, Kobayashi Y, Halpert J R
Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson 85721, USA.
FEBS Lett. 1997 Oct 13;416(1):77-80. doi: 10.1016/s0014-5793(97)01173-3.
Recombinant P450 2B1 wild-type and the active-site mutants I114V, F206L, V363A, V363L, and G478S were purified and studied. The efficiency of coupling of reducing equivalents to 7-hydroxycoumarin formation was decreased for all the mutants except I114V. Uncoupling to H2O was increased for F206L, V363A, and G478S, decreased for V363L, and unchanged for I114V. Uncoupling to H2O2 was increased for V363L and decreased for I114V, F206L, and V363A. The findings from this study provide firm biochemical evidence that residues 206, 363, and 478 comprise part of the substrate binding site of P450 2B1.
纯化并研究了重组细胞色素P450 2B1野生型及其活性位点突变体I114V、F206L、V363A、V363L和G478S。除I114V外，所有突变体将还原当量与7-羟基香豆素形成偶联的效率均降低。F206L、V363A和G478S与水的解偶联增加，V363L与水的解偶联减少，I114V与水的解偶联不变。V363L与过氧化氢的解偶联增加，I114V、F206L和V363A与过氧化氢的解偶联减少。本研究结果提供了确凿的生化证据，表明206、363和478位残基构成了细胞色素P450 2B1底物结合位点的一部分。
