TY - JOUR
T1 - Kinetic characterization of Compound I formation in the thermostable cytochrome P450 CYP119
AU - Kellner, David G.
AU - Hung, Shao Ching
AU - Weiss, Kara E.
AU - Sligar, Stephen G.
PY - 2002/3/22
Y1 - 2002/3/22
N2 - The kinetics of formation and breakdown of the putative active oxygenating intermediate in cytochrome P450, a ferryl-oxo-(π) porphyrin cation radical (Compound I), have been analyzed in the reaction of a thermostable P450, CYP119, with meta-chloroperoxybenzoic acid (m-CPBA). Upon rapid mixing of m-CPBA with the ferric form of CYP119, an intermediate with spectral features characteristic of a ferryl-oxo-(π) porphyrin cation radical was clearly observed and identified by the absorption maxima at 370, 610, and 690 nm. The rate constant for the formation of Compound I was 3.20 (±0.3) × 105 M-1 s-1 at pH 7.0, 4 °C, and this rate decreased with increasing pH. Compound I of CYP119 decomposed back to the ferric form with a first order rate constant of 29.4 ± 3.4 s-1, which increased with increasing pH. These findings form the first kinetic analysis of Compound I formation and decay in the reaction of m-CPBA with ferric P450.
AB - The kinetics of formation and breakdown of the putative active oxygenating intermediate in cytochrome P450, a ferryl-oxo-(π) porphyrin cation radical (Compound I), have been analyzed in the reaction of a thermostable P450, CYP119, with meta-chloroperoxybenzoic acid (m-CPBA). Upon rapid mixing of m-CPBA with the ferric form of CYP119, an intermediate with spectral features characteristic of a ferryl-oxo-(π) porphyrin cation radical was clearly observed and identified by the absorption maxima at 370, 610, and 690 nm. The rate constant for the formation of Compound I was 3.20 (±0.3) × 105 M-1 s-1 at pH 7.0, 4 °C, and this rate decreased with increasing pH. Compound I of CYP119 decomposed back to the ferric form with a first order rate constant of 29.4 ± 3.4 s-1, which increased with increasing pH. These findings form the first kinetic analysis of Compound I formation and decay in the reaction of m-CPBA with ferric P450.
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U2 - 10.1074/jbc.C100745200
DO - 10.1074/jbc.C100745200
M3 - Article
C2 - 11799104
AN - SCOPUS:0037155911
SN - 0021-9258
VL - 277
SP - 9641
EP - 9644
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 12
ER -