Effects of N-terminal modification of recombinant human cytochrome P450 1A2 on catalytic activity.
1. The high-level expression of mammalian cytochrome P450 in bacteria usually requires modification of the amino-terminal region of the enzyme. The effect of altering amino acids in the N-terminus of human recombinant CYP1A2 on its catalytic activity was investigated herein. 2. Rates of 7-ethoxyresorufin O-deethylation by CYP1A2a (a form made by altering the amino acids LLL of CYP1A2 to RER at positions 3-5) in reconstituted systems were significantly low compared with those of other CYP1A2 N-terminal variants at a low ratio of cytochrome P450 to NADPH-cytochrome P450 reductase, but not at higher reductase concentrations. 3. CYP1A2a-dependent ethoxyresorufin O-deethylase activity in a cumene hydroperoxide-supported system was approximately 2-fold higher than other CYP1A2 N-terminal variants. 4. Our results suggest that modification of three N-terminal amino acids in CYP1A2 alters the interaction between CYP1A2 and the reductase in reconstituted phospholipid vesicles and in the bicistronic membranes.
Kim
H-J
HJ
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Lee
S-B
SB
Guengerich
F P
FP
Park
Y I
YI
Dong
M-S
MS
D000595:Amino Acid Sequence; D002384:Catalysis; D019388:Cytochrome P-450 CYP1A2 / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D008567:Membranes, Artificial; D016296:Mutagenesis; D010078:Oxazines / Q000737:chemistry; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics
D008567:Membranes, Artificial; D010078:Oxazines; D011994:Recombinant Proteins; C007649:ethoxyresorufin; C504573:CYP1A2 protein, human; D019388:Cytochrome P-450 CYP1A2