Rhodotorula minuta, a red yeast, produces a cytochrome P450, tentatively named P450rm, catalyzing the formation of isobutene from isovalerate. We found that P450rm interacted with benzoate and the dissociation constant of P450rm for benzoate was 36 microM. A reconstituted system that consisted of purified P450rm and cytochrome P450 reductase catalyzed the 4-hydroxylation of benzoate in addition to the formation of isobutene; the turnover rate was approximately 40 nmol/min/nmol P450rm. The P450rm-monooxygenase system was specific for benzoate and did not catalyze hydroxylation of other aromatic carboxylates. Since only a benzoate 4-hydroxylase that requires tetrahydropteridine has been isolated to date, P450rm appears to be the first isolated cytochrome P450 that acts as a benzoate 4-hydroxylase. The P450rm-monooxygenase system in microsomes of R. minuta might function in the degradation of L-phenylalanine on the pathway to beta-ketoadipate.
Cytochrome P450rm from Rhodotorula minuta catalyzes 4-hydroxylation of benzoate. Publishing Authors By Initials
