A critical role of protein-bound water in the catalytic cycle of cytochrome P-450 camphor.
The rates of NADH oxidation during the hydroxylation of camphor by cytochrome P-450cam were followed in the presence of co-solvents used to increase the osmotic pressure surrounding the protein-bound water. As a result, the measured Vmax decreases independently of the perturbant tested. Roughly 28 molecules of water, involved during the catalytic cycle, are deduced from the variation of Vmax as a function of osmotic pressure. These molecules, in part, could be those present in the cytochrome P-450cam-putidaredoxin interface.
Di Primo
C
C
INSERM-INRA U310, Institut de Biologie Physico-Chimique, Paris, France.
Sligar
S G
SG
Hoa
G H
GH
Douzou
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P
D019475:Camphor 5-Monooxygenase; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009997:Osmotic Pressure; D010084:Oxidation-Reduction; D014867:Water / Q000378:metabolism*
D014867:Water; D009243:NAD; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019475:Camphor 5-Monooxygenase