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Biochem Biophys Res Commun

Title:		Cytochrome b5 promotes the synthesis of delta 16-C19 steroids by homogeneous cytochrome P-450 C21 side-chain cleavage from pig testis
Author(s):		Nakajin S; Takahashi M; Shinoda M; Hall PF;
Address:
Journal Title:		Biochem Biophys Res Commun
Year:		1985
Volume:		132
Issue:		2
Page Number:		708 - 713
DOI:		10.1016/0006-291x(85)91190-8
ISSN/ISBN:		0006-291X (Print) 0006-291X (Linking)
Abstract:		"Conversion of progesterone to 17 alpha-hydroxyprogesterone plus androstenedione (17 alpha-hydroxylation) and to androstadienone (delta 16 synthetase activity) by microsomes from neonatal pig testis, were both inhibited by antibodies raised against homogeneous cytochrome P-450 C21 side-chain cleavage. Inhibition of the two activities showed the same relationship to the concentration of antibody added. Analogous results were obtained with pregnenolone as substrate. In a reconstituted enzyme system consisting of the homogeneous cytochrome P-450 C21 side-chain cleavage enzyme, P-450 reductase and NADPH, addition of cytochrome b5 resulted in the synthesis of the corresponding delta 16-C19-steroid from progesterone (androstadienone) and pregnenolone (androstadienol). The effect of cytochrome b5 was concentration-dependent and prevented by anti-cytochrome b5. It is concluded that the cytochrome P-450 C21 side-chain cleavage enzyme from pig testicular microsomes is also capable of synthesizing delta 16-C19-steroids and is, therefore, likely to be responsible for the large amounts of the pherormone androstadienone produced by male pigs"
Keywords:		Aldehyde-Lyases/isolation & purification/*metabolism Androstadienes/biosynthesis Androstenols/biosynthesis Animals Cytochrome b Group/*metabolism Cytochromes b5 Male Microsomes/enzymology Multienzyme Complexes/*metabolism NADP/metabolism NADPH-Ferrihemopr;
Notes:		"MedlineNakajin, S Takahashi, M Shinoda, M Hall, P F eng AM28113/AM/NIADDK NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 1985/10/30 Biochem Biophys Res Commun. 1985 Oct 30; 132(2):708-13. doi: 10.1016/0006-291x(85)91190-8"