title: Properties of a membrane-associated benzoate-4-hydroxylase from Rhodotorula graminis.
abstract: Membrane fractions of benzoate-induced Rhodotorula graminis hydroxylated benzoate in the para position as demonstrated by high-performance liquid chromatography and isotopic thin-layer chromatography. Benzoate-4-hydroxylase activity was linear as a function of enzyme concentration (washed membranes) and time, and exhibited a pH optimum of 7.6. The enzyme utilized NADPH as a source of reducing equivalents, and was stimulated by FAD. The Km's for benzoate and NADPH were calculated as approximately 2.9 X 10(-5) M and approximately -1.9 X 10(-5) M, respectively. The particulate nature of benzoate-4-hydroxylase together with the fact that the enzyme was pteridine-independent indicates that it is distinct from the isofunctional enzyme previously described in filamentous fungi.
mesh_terms: D001565:Benzoates; D019817:Benzoic Acid; D007700:Kinetics; D008566:Membranes / Q000201:enzymology; D003904:Mitosporic Fungi / Q000201:enzymology*; D009249:NADP; D010105:Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012248:Rhodotorula / Q000201:enzymology*
chemical_list: D001565:Benzoates; D009249:NADP; D019817:Benzoic Acid; D010105:Oxygenases; C019766:benzoate 1,2-dioxygenase