Tetralin as a substrate for camphor (cytochrome P450) 5-monooxygenase

Arch Biochem Biophys. 1996 Aug 15;332(2):239-47. doi: 10.1006/abbi.1996.0338.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Camphor 5-Monooxygenase / chemistry
  • Camphor 5-Monooxygenase / isolation & purification
  • Camphor 5-Monooxygenase / metabolism*
  • Kinetics
  • Naphthols / metabolism
  • Protein Conformation
  • Pseudomonas putida / enzymology
  • Substrate Specificity
  • Tetrahydronaphthalenes / metabolism*
  • Tetralones*
  • Thermodynamics

Substances

  • Naphthols
  • Tetrahydronaphthalenes
  • Tetralones
  • tetralol
  • Camphor 5-Monooxygenase
  • tetralin