Cytochrome P-450 Enzymes in Sterol Biosynthesis and Metabolism

Expression, microsomal and mitochondrial activities of cytochrome P450 enzymes in brain regions from control and phenobarbital-treated rabbits

“…The presence of NADPH cytochrome c reductase activity, necessary for providing the reductase component for the function of the microsomal CYP-dependent monooxygenases, was similar in the microsomes from cortex, midbrain and cerebellum but, in contrast to the behaviour previously reported in the rat brain (Upadhya et al, 2002), was not inducible by phenobarbital. In mitochondria, however, another electron transfer system is responsible for sustaining CYP-catalysed reactions (Jefcoate, 1986). There were differences among the microsomal activities, apart from EFCOD, in the three brain regions (see Table 4).…”

Induction of functional cytochrome P450 and its involvement in degradation of benzoic acid by Phanerochaete chrysosporium

“…Cytochrome P450s are widely distributed hemoproteins involved in various steps of the biosynthesis of endogenous compounds (Jefcoate 1986;Omura 1999;Waterman et al 1986) and in the oxidative detoxification and elimination of many hydrophobic xenobiotics including pollutants, drugs and pesticides (Omura 1999;Wislocki et al 1980). About 150 P450 genes, which compose the largest P450 contingent known to date in fungi, have been found in P. chrysosporium (Doddapaneni and Yadav 2005;Martinez et al 2004).…”

The influence of Aspalathus linearis (Rooibos) and dihydrochalcones on adrenal steroidogenesis: Quantification of steroid intermediates and end products in H295R cells

“…Cytochrome P450 21-hydroxylase (CYP21) hydroxylates PROG and 17OH-PROG to yield the substrates for cytochrome P450 11␤-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2). The latter catalyses the biosynthesis of the mineralocorticoid, aldosterone (ALDO), from deoxycorticosterone (DOC), while CYP11B1 catalyses the conversion of DOC and deoxycortisol to the glucocorticoids, corticosterone (CORT) and cortisol, respectively [2]. In addition to the major steroid hormones, the adrenal also produces, amongst others, sex steroids, albeit at low levels, as well as cortisone, 11-dehydrocorticosterone (11-DHC) and 11␤-hydroxyandrostenedione (11␤OH-A4), at significantly higher levels [3].…”