title: Multiplicity of progesterone 21-hydroxylase activities associated with constitutive forms of rabbit liver cytochrome P-450.
abstract: Constitutive cytochromes P-450 have been solubilized from untreated outbred New Zealand White rabbit liver microsomes. Gradient phosphate buffer elution of DEAE-cellulose columns partially resolved six P-450 fractions. Progesterone 21-hydroxylase activity was reconstituted with several fractions and inhibited by an antibody towards P-450 Form 1. One fraction (LM3b) preferentially catalysed the 6 beta- and 16 alpha-hydroxylation of progesterone. SDS-PAGE indicated the presence of proteins with mobilities closely related to Form 1 in several fractions that were separated from this isozyme by DEAE-cellulose chromatography. These results suggest that several constitutive P-450 fractions may contribute to the regiospecific 21-hydroxylation of progesterone.
authors.forename: K
authors.initials: K
authors.lastname: Sethumadhavan
authors.forename: I R
authors.initials: IR
authors.lastname: Senciall
mesh_terms: D000818:Animals; D000906:Antibodies; D001189:Aryl Hydrocarbon Hydroxylases; D011232:Chemical Precipitation; D002845:Chromatography; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007158:Immunologic Techniques; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D011374:Progesterone / Q000378:metabolism; D011817:Rabbits; D039181:Steroid 16-alpha-Hydroxylase; D013255:Steroid 21-Hydroxylase / Q000378:metabolism*; D013250:Steroid Hydroxylases / Q000378:metabolism*
chemical_list: D000906:Antibodies; D011374:Progesterone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C450239:CYP2C3 protein, Oryctolagus cuniculus; D000072467:Cytochrome P450 Family 2; D039181:Steroid 16-alpha-Hydroxylase; D013255:Steroid 21-Hydroxylase