Gray R D
J Biol Chem. 1983 Mar 25;258(6):3764-8.
The kinetics of carbon monoxide binding to purified, soluble cytochrome P-450LM2 from liver microsomes of phenobarbital-induced rabbits and P-450LM4 from liver microsomes of 5,6-benzoflavone-induced rabbits was determined in the presence of catalytically essential phospholipid, d-benzphetamine or nonionic detergent (0.1% Tween 80, 0.1% Triton N-101, or 0.3% n-octylglucoside). The kinetics under these conditions was consistent with a two-step binding mechanism consisting of bimolecular association followed by a unimolecular rearrangement step. However, when d-benzphetamine was added to P-450LM2 in the presence of sonicated dilauroylglyceryl-3-phosphorylcholine (0.15 mM) or any of the above detergents, CO binding followed simple second order kinetics with a bimolecular rate constant of approximately 3 x 10 M-1 s-1 at 20 degrees C. P-450LM4-CO binding kinetics was not affected by concurrent addition of phospholipid and d-benzphetamine. These results imply that simultaneous binding of amphiphile and substrate induces a conformation of reduced P-450LM2 which is different from that found when either substance is bound alone.
在存在催化必需磷脂、d-苄非他明或非离子去污剂（0.1%吐温80、0.1% Triton N - 101或0.3%正辛基葡糖苷）的情况下，测定了一氧化碳与来自苯巴比妥诱导的兔肝脏微粒体的纯化可溶性细胞色素P - 450LM2以及来自5,6 - 苯并黄酮诱导的兔肝脏微粒体的P - 450LM4的结合动力学。这些条件下的动力学与由双分子缔合随后是单分子重排步骤组成的两步结合机制一致。然而，当在超声处理的二月桂酰甘油 - 3 - 磷酸胆碱（0.15 mM）或上述任何一种去污剂存在下将d-苄非他明添加到P - 450LM2中时，CO结合遵循简单的二级动力学，在20℃时双分子速率常数约为3×10 M⁻¹ s⁻¹。P - 450LM4 - CO结合动力学不受磷脂和d-苄非他明同时添加的影响。这些结果表明两亲物和底物的同时结合诱导了还原型P - 450LM2的一种构象，该构象不同于单独结合任何一种物质时所发现的构象。
