Tetralin as a substrate for camphor (cytochrome P450) 5-monooxygenase.
Camphor (cytochrome P450) 5-monooxygenase, originally isolated from the bacterium Pseudomonas putida PgG 786, catalyzes the essentially stereospecific conversion of tetralin (1,2,3,4-tetrahydronaphthalene) to (R)-1-tetralol ((R).(-)-1,2,3,4-tetrahydro-1-naphthol): tetralin(aq) + NADH(aq) + O2(aq) = (R)-1-tetralol(aq) + NAD(aq) + H2O(l). The ratio of the amount of (S)-1-tetralol to the amount of (R)-1-tetralol is small (approximately 0.04) and the reaction is essentially stereospecific. The reaction time-course plot indicates the formation of additional product(s) from the (R)-1-tetralol. It is found that the above reaction obeys Michaelis-Menten kinetics and that dimethyl sulfoxide, methanol, and p-dioxane serve as accelerators. Approximate values of a Michaelis constant Km, limiting rate Vmax, and catalytic constant kcat are obtained for this reaction under a specified set of conditions. It is shown by means of a thermochemical cycle calculation that the apparent equilibrium constant for this reaction is approximately 4 x 10(65) at T = 298.15 K and pH 7.3. Thus, this reaction is "irreversible" and, unless the enzyme system is inactivated, it will proceed in the direction of complete formation of 1-tetralol from tetralin. A detailed description of the preparation of the camphor (cytochrome P450) 5-monooxygenase enzyme system from recombinant microorganisms is given.
Grayson
D A
DA
Department of Chemical Engineering, University of California at Los Angeles 90095, USA.
Tewari
Y B
YB
Mayhew
M P
MP
Vilker
V L
VL
Goldberg
R N
RN
D019475:Camphor 5-Monooxygenase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D009284:Naphthols / Q000378:metabolism; D011487:Protein Conformation; D016958:Pseudomonas putida / Q000201:enzymology; D013379:Substrate Specificity; D013764:Tetrahydronaphthalenes / Q000378:metabolism*; D044024:Tetralones; D013816:Thermodynamics
D009284:Naphthols; D013764:Tetrahydronaphthalenes; D044024:Tetralones; C019106:tetralol; D019475:Camphor 5-Monooxygenase; C095210:tetralin