Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1982 May;69(5):1013–1017. doi: 10.1104/pp.69.5.1013

Metabolism of Monoterpenes: Conversion of l-Menthone to l-Menthol and d-Neomenthol by Stereospecific Dehydrogenases from Peppermint (Mentha piperita) Leaves 1,2

Robert Kjonaas 1, Charlott Martinkus-Taylor 1, Rodney Croteau 1,3
PMCID: PMC426349  PMID: 16662335

Abstract

The monoterpene ketone l-menthone is specifically converted to l-menthol and l-menthyl acetate and to d-neomenthol and d-neomenthyl-β-d-glucoside in mature peppermint (Mentha piperita L. cv. Black Mitcham) leaves. The selectivity of product formation results from compartmentation of the menthol dehydrogenase with the acetyl transferase and that of the neomenthol dehydrogenase with the glucosyl transferase. Soluble enzyme preparations, but not particulate preparations, from mature peppermint leaves catalyzed the NADPH-dependent reduction of l-menthone to both epimeric alcohols, and the two dehydrogenases responsible for these stereospecific transformations were resolved by affinity chromatography on Mātrex Gel Red A. Both enzymes have a molecular weight of approximately 35,000, possess a Km for NADPH of about 2 × 10−5m, are very sensitive to inhibition by thiol-directed reagents, and are not readily reversible. The menthol dehydrogenase showed a pH optimum at 7.5, exhibited a Km for l-menthone of about 2.5 × 10−4m, and also reduced d-isomenthone to d-neoisomenthol. The neomenthol dehydrogenase showed a pH optimum at 7.6, exhibited a Km for l-menthone of about 2.2 × 10−5m, and also reduced d-isomenthone to d-isomenthol. These stereochemically distinct, but otherwise similar, enzymes are of key importance in determining the metabolic fate of menthone in peppermint, and they are probably typical of the class of dehydrogenases thought to be responsible for the metabolism of monoterpene ketones during plant development.

Full text

PDF
1013

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bachur N. R. Cytoplasmic aldo-keto reductases: a class of drug metabolizing enzymes. Science. 1976 Aug 13;193(4253):595–597. doi: 10.1126/science.959821. [DOI] [PubMed] [Google Scholar]
  2. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  3. Croteau R., Hooper C. L. Metabolism of Monoterpenes: Acetylation of (-)-Menthol by a Soluble Enzyme Preparation from Peppermint (Mentha piperita) Leaves. Plant Physiol. 1978 May;61(5):737–742. doi: 10.1104/pp.61.5.737. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Croteau R., Martinkus C. Metabolism of Monoterpenes: Demonstration of (+)-Neomenthyl-beta-d-Glucoside as a Major Metabolite of (-)-Menthone in Peppermint (Mentha Piperita). Plant Physiol. 1979 Aug;64(2):169–175. doi: 10.1104/pp.64.2.169. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Loomis W. D. Overcoming problems of phenolics and quinones in the isolation of plant enzymes and organelles. Methods Enzymol. 1974;31:528–544. doi: 10.1016/0076-6879(74)31057-9. [DOI] [PubMed] [Google Scholar]
  6. Martinkus C., Croteau R. Metabolism of Monoterpenes : EVIDENCE FOR COMPARTMENTATION OF l-MENTHONE METABOLISM IN PEPPERMINT (MENTHA PIPERITA) LEAVES. Plant Physiol. 1981 Jul;68(1):99–106. doi: 10.1104/pp.68.1.99. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES