TY - JOUR T1 - JUST HOW INSOLUBLE ARE MONOTERPENES JF - J Chem Ecol Y1 - 1993 A1 - JD WEIDENHAMER A1 - FA MACIAS A1 - NH FISCHER A1 - GB WILLIAMSON SP - 1799–1807 KW - Allelopathy KW - Borneol KW - Calamintha-Ashei KW - Camphor KW - Conradina-Canescens KW - Florida Scrub Community KW - Grasses KW - Juglone KW - Menthofurans KW - Monoterpenes KW - Shrub KW - Solubility KW - Ursolic Acid AB - Prior generalizations about the ecological roles of monoterpenes may be misleading if based on the presumed insolubility of monoterpenes in water. We determined the aqueous solubility of 31 biologically active monoterpenes by gas chromatography. While hydrocarbons were of low solubility (< 35 ppm), oxygenated monoterpenes exhibited solubilities one or two orders of magnitude higher, with ranges of 155-6990 ppm for ketones and of 183-1360 ppm for alcohols. Many monoterpenes are phytotoxic in concentrations under 100 ppm, well below the saturated aqueous concentrations of oxygenated monoterpenes. Therefore, even dilute, unsaturated solutions of monoterpenes, occurring naturally in plant tissues and soil solutions, may act as potent biological inhibitors. VL - 19 UR - http://apps.isiknowledge.com/InboundService.do?product=WOS&action=retrieve&SrcApp=Papers&UT=A1993LT33800016&SID=2AFL5dnj5MCc8JPedL5&SrcAuth=mekentosj&mode=FullRecord&customersID=mekentosj&DestFail=http%253A%252F%252Faccess.isiproducts.com%252Fcustom_image ER - TY - JOUR T1 - Monoterpene metabolism. Cloning, expression, and characterization of (-)-isopiperitenol/(-)-carveol dehydrogenase of peppermint and spearmint JF - Plant Physiol Y1 - 2005 DO - 10.1104/pp.104.053298 A1 - Kerry L Ringer A1 - Edward M Davis A1 - Rodney Croteau SP - 863–72 KW - Alcohol Oxidoreductases KW - Amino Acid Sequence KW - Cloning: Molecular KW - Mentha piperita KW - Mentha spicata KW - Molecular Sequence Data KW - Molecular Structure KW - Monoterpenes KW - Multigene Family KW - Oils: Volatile KW - Phylogeny AB - The essential oils of peppermint (Mentha x piperita) and spearmint (Mentha spicata) are distinguished by the oxygenation position on the p-menthane ring of the constitutive monoterpenes that is conferred by two regiospecific cytochrome P450 limonene-3- and limonene-6-hydroxylases. Following hydroxylation of limonene, an apparently similar dehydrogenase oxidizes (-)-trans-isopiperitenol to (-)-isopiperitenone in peppermint and (-)-trans-carveol to (-)-carvone in spearmint. Random sequencing of a peppermint oil gland secretory cell cDNA library revealed a large number of clones that specified redox-type enzymes, including dehydrogenases. Full-length dehydrogenase clones were screened by functional expression in Escherichia coli using a recently developed in situ assay. A single full-length acquisition encoding (-)-trans-isopiperitenol dehydrogenase (ISPD) was isolated. The (-)-ISPD cDNA has an open reading frame of 795 bp that encodes a 265-residue enzyme with a calculated molecular mass of 27,191. Nondegenerate primers were designed based on the (-)-trans-ISPD cDNA sequence and employed to screen a spearmint oil gland secretory cell cDNA library from which a 5'-truncated cDNA encoding the spearmint homolog, (-)-trans-carveol-dehydrogenase, was isolated. Reverse transcription-PCR amplification and RACE were used to acquire the remaining 5'-sequence from RNA isolated from oil gland secretory cells of spearmint leaf. The full-length spearmint dehydrogenase shares >99% amino acid identity with its peppermint homolog and both dehydrogenases are capable of utilizing (-)-trans-isopiperitenol and (-)-trans-carveol. These isopiperitenol/carveol dehydrogenases are members of the short-chain dehydrogenase/reductase superfamily and are related to other plant short-chain dehydrogenases/reductases involved in secondary metabolism (lignan biosynthesis), stress responses, and phytosteroid biosynthesis, but they are quite dissimilar (approximately 13% identity) to the monoterpene reductases of mint involved in (-)-menthol biosynthesis. The isolation of the genes specifying redox enzymes of monoterpene biosynthesis in mint indicates that these genes arose from different ancestors and not by simple duplication and differentiation of a common progenitor, as might have been anticipated based on the common reaction chemistry and structural similarity of the substrate monoterpenes. VL - 137 ER -