ISSN:
1432-1335
Keywords:
Monooxygenase
;
Cytochrome P-450
;
NADPH-cytochrome P-450 reductase
;
Protein kinase
;
Phosphatase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Two forms of enzymatic posttranslational modifications of the monooxygenase system are described: modification by phosphatase and modification by protein kinase. Phosphatase treatment of microsomes isolated from phenobarbital-pretreated rabbits and rats caused a marked decrease of monooxygenase activity which was paralleled by a comparable decrease of NADPH-cytochrome P-450 reductase activity while the second essential component of the system, cytochrome P-450, remained unaltered. Thus phosphatase attacks monooxygenase via reductase. Protein kinases showed the opposite preference; while cytochrome P-450 was phosphorylated, NADPH-cytochrome P-450 reductase was not. Thus the kinase affects monooxygenase via cytochrome P-450. The phosphorylation of cytochrome P-450 turned out to be a specific reaction observed only with certain cytochrome P-450 isoenzymes and certain protein kinases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00391438
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