title: Inhibition and substrate specificity of yeast delta 22-desaturase.
abstract: Using yeast microsomes, 23-hydroxysterols were tested as intermediates in the formation of the sterol side delta 22-double bond. No evidence could be found supporting a two-stage mechanism of desaturation via hydroxylation and dehydration. Sterols with various side chains were tested as substrates. Those with alkyl substituents in the 24-alpha position were poor substrates. A series of sterols, including cyclopropyl sterols, were tested as mechanism-based inhibitors without success. Inhibition was observed with an isocyano-sterol.
authors: Department of Chemistry, Stanford University, CA 94305.
authors: J L
authors: JL
authors: Giner
authors: C
authors: C
authors: Djerassi
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification / Q000378:metabolism*; D007553:Isotope Labeling / Q000379:methods; D008861:Microsomes / Q000201:enzymology; D015394:Molecular Structure; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D013379:Substrate Specificity; D014316:Tritium
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D014316:Tritium; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; C066577:ERG5 protein, S cerevisiae