| Title |
Monoterpene double-bond reductases of the (−)-menthol biosynthetic pathway: isolation and characterization of cDNAs encoding (−)-isopiperitenone reductase and (+)-pulegone reductase of peppermint
|
|---|---|
| Published in |
Archives of Biochemistry & Biophysics, October 2003
|
| DOI | 10.1016/s0003-9861(03)00390-4 |
| Pubmed ID | |
| Authors |
Kerry L Ringer, Marie E McConkey, Edward M Davis, Gary W Rushing, Rodney Croteau |
| Abstract |
Random sequencing of a peppermint essential oil gland secretory cell cDNA library revealed a large number of clones that specified redox-type enzymes. Full-length acquisitions of each type were screened by functional expression in Escherichia coli using a newly developed in situ assay. cDNA clones encoding the monoterpene double-bond reductases (-)-isopiperitenone reductase and (+)-pulegone reductase were isolated, representing two central steps in the biosynthesis of (-)-menthol, the principal component of peppermint essential oil, and the first reductase genes of terpenoid metabolism to be described. The (-)-isopiperitenone reductase cDNA has an open reading frame of 942 nucleotides that encodes a 314 residue protein with a calculated molecular weight of 34,409. The recombinant reductase has an optimum pH of 5.5, and K(m) values of 1.0 and 2.2 microM for (-)-isopiperitenone and NADPH, respectively, with k(cat) of 1.3s(-1) for the formation of the product (+)-cis-isopulegone. The (+)-pulegone reductase cDNA has an open reading frame of 1026 nucleotides and encodes a 342 residue protein with a calculated molecular weight of 37,914. This recombinant reductase catalyzes the reduction of the 4(8)-double bond of (+)-pulegone to produce both (-)-menthone and (+)-isomenthone in a 55:45 ratio, has an optimum pH of 5.0, and K(m) values of 2.3 and 6.9 microM for (+)-pulegone and NADPH, respectively, with k(cat) of 1.8s(-1). Deduced sequence comparison revealed that these two highly substrate specific double-bond reductases show less than 12% identity. (-)-Isopiperitenone reductase is a member of the short-chain dehydrogenase/reductase superfamily and (+)-pulegone reductase is a member of the medium-chain dehydrogenase/reductase superfamily, implying very different evolutionary origins in spite of the similarity in substrates utilized and reactions catalyzed. |
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Mendeley demographics
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 2 | 2% |
| Japan | 2 | 2% |
| Serbia | 1 | 1% |
| Mexico | 1 | 1% |
| Germany | 1 | 1% |
| Unknown | 86 | 92% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 26 | 28% |
| Student > Ph. D. Student | 17 | 18% |
| Student > Master | 9 | 10% |
| Student > Bachelor | 8 | 9% |
| Professor | 5 | 5% |
| Other | 16 | 17% |
| Unknown | 12 | 13% |
| Readers by discipline | Count | As % |
|---|---|---|
| Agricultural and Biological Sciences | 36 | 39% |
| Biochemistry, Genetics and Molecular Biology | 23 | 25% |
| Chemistry | 4 | 4% |
| Engineering | 4 | 4% |
| Arts and Humanities | 1 | 1% |
| Other | 7 | 8% |
| Unknown | 18 | 19% |