Purification and characterization of a Baeyer-Villiger mono-oxygenase from Rhodococcus erythropolis DCL14 involved in three different monocyclic monoterpene degradation pathways
article
A Baeyer-Villiger mono-oxygenase (BVMO), catalysing the NADPH- and oxygen-dependent oxidation of the monocyclic monoterpene ketones 1-hydroxy-2-oxolimonene, dihydrocarvone and menthone, was purified to homogeneity from Rhodococcus erythropolis DCL14. Monocyclic monoterpene ketone mono-oxygenase (MMKMO) is a monomeric enzyme of molecular mass 60 kDa. It contains 1 mol of FAD/monomer as the prosthetic group. The N-terminal amino acid sequence showed homology with many other NADPH-dependent and FAD-containing (Type 1) BVMOs. Maximal enzyme activity was measured at pH 9 and 35°C. MMKMO has a broad substrate specificity, catalysing the lactonization of a large number of monocyclic monoterpene ketones and substituted cyclohexanones. The natural substrates 1-hydroxy-2-oxo-limonene, dihydrocarvone and menthone were converted stoichiometrically into 3-isopropenyl-6-oxoheptanoate (the spontaneous rearrangement product of the lactone formed by MMKMO), 4-isopropenyl-7-methyl-2-oxo-oxepanone and 7-isopropyl-4-methyl-2-oxo-oxepanone respectively. The MMKMO-catalysed conversion of iso-dihydrocarvone showed an opposite regioselectivity to that of dihydrocarvone; in this case, 6-isopropenyl-3-methyl-2-oxo-oxepanone was formed as the product. MMKMO converted all enantiomers of the natural substrates with almost equal efficiency. MMKMO is involved in the conversion of the monocyclic monoterpene ketone intermediates formed in the degradation pathways of all stereoisomers of three different monocyclic monoterpenes, i.e. limonene, (dihydro)carveol and menthol. Chemicals/CAS: Aldehydes; Cyclohexanones; Enzyme Inhibitors; Flavin-Adenine Dinucleotide, 146-14-5; Menthol, 1490-04-6; menthone, 89-80-5; Metals; monocyclic monoterpeneketone mono-oxygenase, EC 1.14.13.-; Oxygenases, EC 1.13.-; Terpenes
Topics
CarvoneFlavoproteinLimoneneMentholRegioselectivityBacterial enzymeCarvoneCyclohexanone derivativeHeptanoic acid derivativeLimoneneMenthoneTerpeneUnspecific monooxygenaseAmino acid sequenceAmino terminal sequenceBiodegradationEnzyme activityEnzyme analysisEnzyme purificationEnzyme specificityEnzyme structureMolecular weightNonhumanPriority journalRhodococcusSequence homologyStereochemistryAldehydesAmino Acid SequenceBiodegradation, EnvironmentalCatalysisCyclohexanonesEnzyme InductionEnzyme InhibitorsFlavin-Adenine DinucleotideHydrogen-Ion ConcentrationMentholMetalsMolecular Sequence DataMolecular WeightOxygenasesRhodococcusSequence AlignmentSequence Homology, Amino AcidSpectrum AnalysisStereoisomerismSubstrate SpecificityTemperatureTerpenes
TNO Identifier
72166
ISSN
0264602
Source
Biochemical Journal, 347(3), pp. 693-701.
Pages
693-701
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