Demonstration that menthofuran synthase of mint (Mentha) is a cytochrome P450 monooxygenase: cloning, functional expression, and characterization of the responsible gene.

Abstract

(+)-Menthofuran is an undesirable monoterpenoid component of peppermint (Mentha x piperita) essential oil that is derived from the alpha,beta-unsaturated ketone (+)-pulegone. Microsomal preparations, from the oil gland secretory cells of a high (+)-menthofuran-producing chemotype of Mentha pulegium, transform (+)-pulegone to (+)-menthofuran in the presence of NADPH and molecular oxygen, implying that menthofuran is synthesized by a mechanism analogous to that of mammalian liver cytochrome P450s involving the hydroxylation of the syn-methyl group of (+)-pulegone, spontaneous intramolecular cyclization to the hemiketal, and dehydration to the furan. An abundant cytochrome P450 clone from a peppermint oil gland cell cDNA library was functionally expressed in Saccharomyces cerevisiae and Escherichia coli and shown to encode the (+)-menthofuran synthase (i.e., (+)-pulegone-9-hydroxylase). The full-length cDNA contains 1479 nucleotides, and encodes a protein of 493 amino acid residues of molecular weight 55,360, which bears all of the anticipated primary structural elements of a cytochrome P450 and most closely resembles (35% identity) a cytochrome P450 monoterpene hydroxylase, (+)-limonene-3-hydroxylase, from the same source. The availability of this gene permits transgenic manipulation of peppermint to improve the quality of the derived essential oil.

• Authors: C M Bertea, M Schalk, F Karp, M Maffei, R Croteau
• Journal: Archives of biochemistry and biophysics (Arch Biochem Biophys) Vol. 390 Issue 2 Pg. 279-86 (Jun 15 2001) ISSN: 0003-9861 [Print] United States
• PMID: 11396930 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright 2001 Academic Press.

Chemical References

• Cyclohexane Monoterpenes
• DNA, Complementary
• Monoterpenes
• Terpenes
• Menthol
• menthofuran
• pulegone
• Cytochrome P-450 Enzyme System
• Mixed Function Oxygenases
• menthofuran synthase

Topics

• Amino Acid Sequence
• Cloning, Molecular
• Cyclohexane Monoterpenes
• Cytochrome P-450 Enzyme System (genetics, metabolism)
• DNA, Complementary (genetics, isolation & purification)
• Escherichia coli (genetics)
• Lamiaceae (enzymology, metabolism)
• Menthol (analogs & derivatives, metabolism)
• Mixed Function Oxygenases (metabolism)
• Molecular Sequence Data
• Monoterpenes
• Saccharomyces cerevisiae (genetics)
• Sequence Homology, Amino Acid
• Terpenes (metabolism)
• Transfection