the substrate geranyl diphosphate is ionized by diphosphate elimination, resulting in the geranyl cation. Subsequently, this cation is converted into the linalyl cation and alpha-terpinyl cation. The intermediate alpha-terpinyl cation is the precursor for all cyclic monoterpenes. alpha-Terpineol is formed after water capture of the alpha-terpinyl cation. A cyclization reaction resulting in 1,8-cineole uses alpha-terpineol as a precursor
the enzyme releases alpha-terpineol as the main compound as a terpineol synthase (TER). The S to R ratio is 11.2:1 and 10.8:1 in two experimental passages
the formation of alpha-terpineol starts by a nucleophilic attack of water. During this attack, the alpha-terpinyl cation is stabilized by Pi-stacking with a tryptophan side chain (Tryp253). The hypothesized catalytic mechanism of alpha-terpineol-to-1,8-cineole conversion is initiated by a catalytic dyad (His502 and Glu249), acting as a base, and a threonine (Thr278) providing the subsequent rearrangement from terpineol to cineol by catalyzing the autoprotonation of (2S)-2-alpha-terpineol, which is the favored enantiomer product of the recombinant enzymes. Product analysis and quantification by GC-MS
strongest signals with RNA from flower buds and strongly reduced transcript levels in pre- and postanthesis open flowers and in set flowers at early fruit onset
strongest signals with RNA from flower buds and strongly reduced transcript levels in pre- and postanthesis open flowers and in set flowers at early fruit onset
cyclization reactions of monoterpene synthases, overview. Substrate geranyl diphosphate is ionized by diphosphate elimination, resulting in the geranyl cation. Subsequently, this cation is converted into the linalyl cation and alpha-terpinyl cation. The synthesis of the acyclic beta-myrcene might proceed via the geranyl cation or via the linalyl cation by deprotonation. The intermediate alpha-terpinyl cation is the precursor for all cyclic monoterpenes. The 2,7-ring closure results in the pinyl cation, which is deprotonated to synthesize beta-pinene and alpha-pinene. Sabinene, with a cyclopropane ring, is released after two carbocation formations and 2,6-ring closure. alpha-Terpineol is formed after water capture of the alpha-terpinyl cation. Broken lines indicate possible reactions leading to 1,8-cineole. A cyclization reaction resulting in 1,8-cineole uses alpha-terpineol as a precursor
alpha-terpineol is one of the main monoterpenes found in the grape berry (Vitis vinifera) with its concentrations varying in different varieties. Identification of associations between the alpha-terpineol synthase (alpha-TPS) gene, a regulator of alpha-terpineol metabolism, and alpha-terpineol content in different grapevine varieties
the amino acids at positions 147, 148, and 266 determine the different terpineol-cineole ratios in Nicotiana suaveolens cineole synthase and Nicotiana langsdorffii terpineol synthase
oleocellosis is a serious physiological disorder in citrus fruit that mainly results in appearance and quality deterioration. Large changes in the volatile profiles and gene expression in terpenoid metabolism are observed in oleocellosis peels compared to healthy ones. For gene expressions in terpenoid metabolism, the upregulated genes aldehyde dehydrogenase (NAD+) (ALDH) and the downregulated genes beta-caryophyllene synthase 1 (BCS1), alpha-terpineol synthase 2 (TES2), and myrcene synthase (MS) are the main differences in oleocellosis peels
oleocellosis is a serious physiological disorder in citrus fruit that mainly results in appearance and quality deterioration. Large changes in the volatile profiles and gene expression in terpenoid metabolism are observed in oleocellosis peels compared to healthy ones. For gene expressions in terpenoid metabolism, the upregulated genes aldehyde dehydrogenase (NAD+) (ALDH) and the downregulated genes beta-caryophyllene synthase 1 (BCS1), alpha-terpineol synthase 2 (TES2), and myrcene synthase (MS) are the main differences in oleocellosis peels
gene TER, DNA and amino acid sequence determination and analysis, sequence comparisons, recombinant overexpression of His-tagged wild-type enzyme in Escherichia coli strain HMS 174(DE3)
Vitis vinifera terpenoid cyclases: functional identification of two sesquiterpene synthase cDNAs encoding (+)-valencene synthase and (-)-germacrene D synthase and expression of mono- and sesquiterpene synthases in grapevine flowers and berries
Identification of Vitis vinifera (-)-alpha-terpineol synthase by in silico screening of full-length cDNA ESTs and functional characterization of recombinant terpene synthase
Mirzaei, F.; Fatehi, F.; Ismaili, A.; Yaghotipoor, A.; Qaderi, A.
Expression of genes 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), sabinene synthase (Tctps1) and alpha-terpineol synthase (Tctps5) and its relation to thymol and carvacrol biosynthesis in Thymus vulgaris under water deficit stress