The role of cytochrome P450 lysine residues in the interaction between cytochrome P450IA1 and NADPH-cytochrome P450 reductase.
The role of cytochrome P450 lysine residues in the interaction between cytochrome P450IA1 and NADPH-cytochrome P450 reductase.
复制标题
细胞色素 P450 赖氨酸残基在细胞色素 P450IA1 和 NADPH-细胞色素 P450 还原酶之间相互作用中的作用。
DOI：
10.1016/0003-9861(92)90140-r
复制
发表时间：
1992
影响因子：
3.9
通讯作者：
Strobel,HW
中科院分区：
文献类型：
--
作者：
Shen,S;Strobel,HW
细胞色素P450 IA 1（从β-萘啶酮处理的大鼠肝微粒体中纯化）已用赖氨酸修饰剂乙酸酐共价修饰。细胞色素P450 IA 1中不同水平的赖氨酸残基修饰可以通过改变乙酸酐的浓度来实现。P450 IA 1的赖氨酸残基的修饰极大地抑制了P450 IA 1与NADPH-细胞色素P450还原酶的相互作用。1.0和3.3摩尔赖氨酸残基每摩尔P450 IA 1的修改导致在30%和95%的下降，分别在7-乙氧基香豆素羟基化的重组P450 IA 1/还原酶复合物。然而，每摩尔P450 IA 1的3.3摩尔赖氨酸残基的修饰仅使枯烯过氧化氢支持的P450依赖性7-乙氧基香豆素羟基化降低30%。光谱和荧光研究表明，没有迹象表明全球构象变化的P450 IA 1，甚至高达8.8摩尔赖氨酸残基修饰每摩尔P450 IA 1。这些数据表明，至少有三个赖氨酸残基的P450 IA 1可能参与与还原酶的相互作用。通过[14 C]乙酸酐修饰、胰蛋白酶消化、HPLC分离和氨基酸测序鉴定P450 IA 1中可能参与这种相互作用的赖氨酸残基。以这种方式鉴定的候选赖氨酸残基是K97、K271、K279和K407。
Cytochrome P450IA1 (purified from hepatic microsomes of β-naphthoflavone-treated rats) has been covalently modified with the lysine-modifying reagent acetic anhydride. Different levels of lysine residue modification in cytochrome P450IA1 can be achieved by varying the concentration of acetic anhydride. Modification of lysine residues in P450IA1 greatly inhibits the interaction of P450IA1 with NADPH-cytochrome P450 reductase. Modification of 1.0 and 3.3 mol lysine residues per mole P450IA1 resulted in 30 and 95% decreases, respectively, in 7-ethoxycoumarin hydroxylation by a reconstituted P450IA1/reductase complex. However, modification of 3.3 mol lysine residues per mole P450IA1 decreased only cumene hydroperoxide-supported P450-dependent 7-ethoxycoumarin hydroxylation by 30%. Spectral and fluorescence studies showed no indication of global conformational change of P450IA1 even with up to 8.8 mol lysine residues modified per mole P450IA1. These data suggest that at least three lysine residues in P450IA1 may be involved in the interaction with reductase. Identification of lysine residues in P450IA1 possibly involved in this interaction was carried out by [14C]acetic anhydride modification, trypsin digestion, HPLC separation, and amino acid sequencing. The lysine residue candidates identified in this manner were K97, K271, K279, and K407.