title: Metabolic conditions determining the composition and catalytic activity of cytochrome P-450 monooxygenases in Candida tropicalis.
abstract: In the microsomal fraction of Candida tropicalis cells, two distinct monooxygenases were detected, depending on the growth conditions. The distinction of the two monooxygenases was evident from: (i) the absorption maxima in the reduced CO difference spectra of the terminal oxidases (cytochromes P-450 and P-448); (ii) the contents of the monooxygenase components (cytochromes P-450/P-448, NADPH-cytochrome c (P-450) reductase, and cytochrome b5) and (iii) the catalytic activity of the complete system (aliphatic hydroxylation and N-demethylation activity). The occurrence of the respective monooxygenases could be related to the carbon source (n-alkanes or glucose). Oxygen limitation led to a significant increase of cytochrome P-450/P-448 content, independent of the carbon source utilized by the cells. An improved method for the isolation of microsomes enabled us to demonstrate the presence of cytochrome P-448 in glucose-grown cells.
mesh_terms: D000473:Alkanes / Q000378:metabolism; D002175:Candida / Q000032:analysis / Q000201:enzymology*; D002384:Catalysis; D003470:Culture Media / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System; D003580:Cytochromes / Q000032:analysis; D005947:Glucose / Q000378:metabolism; D008861:Microsomes / Q000032:analysis / Q000201:enzymology; D010105:Oxygenases / Q000032:analysis / Q000378:metabolism*
chemical_list: D000473:Alkanes; D003470:Culture Media; D003580:Cytochromes; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D005947:Glucose