INFLUENCE OF FLAVIN ADDITION AND REMOVAL ON THE FORMATION OF SUPEROXIDE BY NADPH-CYTOCHROME-P-450 REDUCTASE - A SPIN-TRAP STUDY
INFLUENCE OF FLAVIN ADDITION AND REMOVAL ON THE FORMATION OF SUPEROXIDE BY NADPH-CYTOCHROME-P-450 REDUCTASE - A SPIN-TRAP STUDY
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DOI：
10.1016/0003-9861(81)90348-9
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发表时间：
1981-01-01
影响因子：
3.9
通讯作者：
PIETTE, LH
中科院分区：
文献类型：
--
作者：
GROVER, TA;PIETTE, LH
使用自旋捕集器5，5-二甲基-1-吡咯啉-1-氧化物测量[大鼠肝脏]细胞色素P-450还原酶氧化NADPH期间发生的超氧化物的形成，细胞色素P-450还原酶是一种黄素蛋白，每条多肽链含有1个FMN和FAD分子。酶将氧还原为超氧化物的能力似乎同样取决于其FMN和FAD的含量。从还原酶中选择性去除FMN可减少超氧化物的形成，其量相当于天然和耗尽的蛋白质制剂之间总黄素（FMN和FAD）浓度的差异。相反，还原酶结合的FMN是必要的电子转移到另一个受体，细胞色素c，但不是铁氰化物。还原酶的天然制备物的NADPH氧化和伴随的超氧化物的形成通过添加核黄素、FMN和FAD来刺激，其中核黄素是最有效的。添加的黄素可被细胞色素P-450还原酶还原为电子受体，并增加其自氧化产生的超氧化物的形成。
The spin-trap 5,5-dimethyl-1-pyrroline-1-oxide was used to measure the formation of superoxide that occurs during the oxidation of NADPH by [rat liver] cytochrome P-450 reductase, a flavoprotein containing 1 molecule each of FMN and FAD per polypeptide chain. The enzyme''s ability to reduce oxygen to superoxide appears to be equally dependent on its content of FMN and FAD. Selective removal of FMN from reductase decreases superoxide formation by an amount equivalent to the difference in total flavin (FMN and FAD) concentration between native and depleted preparations of the protein. In contrast, reductase-bound FMN is necessary for the transfer of electrons to another acceptor, cytochrome c, but not to ferricyanide. NADPH oxidation and the concomitant formation of superoxide by native preparations of reductase are stimulated by the addition of riboflavin, FMN and FAD with riboflavin being the most effective. Added flavins may be reduced by cytochrome P-450 reductase as electron acceptors with increased superoxide formation resulting from their autooxidation.