Some new aspects of damage to @entity1447 peroxidase activities by a toxic @entity2625 were investigated. @entity69605 (MEKP) damage to @entity1447 and inhibition of @entity1447 -mediated peroxidase activities were studied. In vivo, hepatic microsomal @entity2125 - and @entity1110 -peroxidase activities were induced in @entity35 by @entity109 and @entity5954 . @entity109 treatment induced more @entity2125 - and @entity1110 -peroxidase activity than did @entity5954 treatment. In vitro, microsomal @entity1447 from @entity35 liver was more sensitive to damage by MEKP than was this protein from @entity35 kidney. Destruction of @entity1447 hemoprotein and inhibition of its associated peroxidase activities by MEKP increased as a function of time of exposure to the @entity2625 . The addition of MEKP to microsomes resulted in a progressive increase in spectral absorbance at 433 nm. MEKP was an irreversible inhibitor of @entity2125 - and @entity1110 -peroxidase, and @entity2125 -peroxidase was more sensitive to damage than was @entity1110 -peroxidase. At 0 time and low concentration, MEKP was immediately bound to microsomal @entity1447 and it exhibited competitive inhibition of @entity2125 - and @entity1110 -peroxidase. At high concentration, MEKP was a mixed inhibitor of @entity2125 - and @entity1110 -peroxidase. This study also showed that MEKP is a substrate for microsomal P-450 peroxidase activities and suggests that these peroxidase activities may play an important role in metabolism of toxic lipophilic organic @entity2627 that enter the endoplasmic reticulum.

@entity69605 damage to XXXX peroxidase activities.

@entity1447 :: ('25251(Tax:10116)', 'Gene') :: ['cytochrome P-450'] @entity2125 :: ('MESH:D009243', 'Chemical') :: ['NADH'] @entity2627 :: ('MESH:D010545', 'Chemical') :: ['peroxides'] @entity2625 :: ('CHEBI:44785', 'Chemical') :: ['peroxide'] @entity1110 :: ('MESH:D009249', 'Chemical') :: ['NADPH'] @entity109 :: ('MESH:D010634', 'Chemical') :: ['phenobarbital', 'Phenobarbital'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats'] @entity5954 :: ('MESH:D008748', 'Chemical') :: ['3-methylcholanthrene'] @entity69605 :: ('MESH:C011007', 'Chemical') :: ['Methyl ethyl ketone peroxide']
@entity1447 :: (25251(Tax:10116),Gene) :: ['cytochrome P-450']
