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1798720 
Journal Article 
Cumene hydroperoxide-supported demethylation reactions catalyzed by cytochrome P450 2B4 lacking the NH2-terminal sequence 
Zhang, YQ; Pernecky, SJ 
1999 
Yes 
Biochemical and Biophysical Research Communications
ISSN: 0006-291X
EISSN: 1090-2104 
258 
1 
32-38 
English 
10222230 
WOS:000080058800007 
Catalytic activities of cytochrome P450 2B4 lacking NH2-terminal amino acids 2-27 (wt Delta2B4) and that of truncated 2B4 containing a Pro to Ser mutation at position 221 were examined in a system supported by cumene hydroperoxide. Demethylation activities of either truncated 2B4 with N-methylaniline, N,N-dimethylaniline, and d-benzphetamine were lower than those of liver microsomal 2B4, whereas the rate of 1-phenylethanol oxidation to acetophenone catalyzed by liver microsomal and truncated 2B4 enzymes was nearly the same. The Km and Vmax values for cumene hydroperoxide in the demethylation of N-methylaniline by wt Delta2B4 were 20% and 28%, respectively, of those obtained for 2B4. The reaction with wt Delta2B4 displayed a lesser dependence on phospholipid than did that with 2B4, and a complex relationship between activity and substrate concentration. The results suggest that the NH2-terminal region contributes to interaction of oxidant, substrate, and phospholipid in cumene hydroperoxide-supported reactions catalyzed by cytochrome P450 2B4. 
cytochrome P450; hydroperoxides; heterologous expression