α-Farnesene: Isolation from the natural coating of apples

Murray, KE

doi:10.1071/ch9690197

Cited by 67 publications

(30 citation statements)

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“…For these reasons we used the procedure (b) for the identification of terpenes and procedure (a) to study the composition of the paraffins and fatty acids. Procedure (b) carried out separately on both the hexane and CHC13 extracts of the stems yielded two oils: the first was 17 3-Farnesene IC < 1 MS [14] 18 Humulene IC < 1 MS, KI [9] 19 Alloaromadendrene IB, IC < 1 MS [9] 20 Eremophilene IC 1 MS [9] 21 3-Bisabolene IC < 1 MS [9] 22 [12] no Compounds…”

Section: Resultsmentioning

confidence: 99%

Constituents of Essential Oil ofAframomum giganteum

Bernardi

Mellerio²,

Paternoster-Colombo³

et al. 1981

Planta Med

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Section: Resultsmentioning

confidence: 99%

Constituents of Essential Oil ofAframomum giganteum

Bernardi

Mellerio²,

Paternoster-Colombo³

et al. 1981

Planta Med

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“…In each case, mass spectra were similar to those obtained from authentic materials and to published spectra: farnesenes, Murray (1969) and Anet ( 1970); monoterpenes, Ryhage and von Sydow (1963);2-phenylethanol, Mass Spectrometry Data Centre (1975); 2-phenylethyl isothiocyanate, Kjaer et al (1963).…”

Section: Identification Of Compoundsmentioning

confidence: 94%

Composition of aphid alarm pheromones

1980

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Abstract--Analysis of single cornicle droplets from six species of aphid showed the presence of volatile components in addition to (E)-/3-farnesene. Compounds identified included ( Z,E)-a-and (E,E)-a-farnesene forMyzus persicae and a-and fl-pinene for Megoura viciae. With Megoura viciae, (-)-a-pinene was most important for alarm activity. The major component of the alarm pheromone of Phorodon humuli was (E)-fl-farnesene even though farnesenes are present in the summer host Humulus lupulus.

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“…The oven temperature ramp was 35°C for 1 min, 5°C min Ϫ1 to 240°C, and hold for 1 min. Authentic compound retention time standards used were E-␤-farnesene (Givaudan, Switzerland), and Z,E-and E,E-␣-farnesene obtained from "Granny Smith" apples (47,48), and quantification was against hexadecane.…”

Section: Methodsmentioning

confidence: 99%

Defining the Potassium Binding Region in an Apple Terpene Synthase

Green

Squire

Nieuwenhuizen

et al. 2009

Journal of Biological Chemistry

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Terpene synthases are a family of enzymes largely responsible for synthesizing the vast array of terpenoid compounds known to exist in nature. Formation of terpenoids from their respective 10-, 15-, or 20-carbon atom prenyl diphosphate precursors is initiated by divalent (M 2؉ ) metal ion-assisted electrophilic attack. In addition to M 2؉ , monovalent cations (M ؉ ) have also been shown to be essential for the activity of certain terpene synthases most likely by facilitating substrate binding or catalysis. An apple ␣-farnesene synthase (MdAFS1), which has a dependence upon potassium (K ؉ ), was used to identify active site regions that may be important for M ؉ binding. Protein homology modeling revealed a surface-exposed loop (H-␣l loop) in MdAFS1 that fulfilled the necessary requirements for a K ؉ binding region. Site-directed mutagenesis analysis of specific residues within this loop then revealed their crucial importance to this K ؉ response and strongly implicated specific residues in direct K ؉ binding. The role of the H-␣l loop in terpene synthase K ؉ coordination was confirmed in a Conifer pinene synthase also using site-directed mutagenesis. These findings provide the first direct evidence for a specific M ؉ binding region in two functionally and phylogenetically divergent terpene synthases. They also provide a basis for understanding K ؉ activation in other terpene synthases and establish a new role for the H-␣l loop region in terpene synthase catalysis.Terpenoids comprise the largest and most diverse class of natural products known (1). Terpenoid structures range from simple acyclic molecules to complex heterocyclic ring systems. These compounds are synthesized by a large family of enzymes called terpene synthases (TPS). 2 In plants, monoterpenes (C10-based) are synthesized from the plastidderived geranyl diphosphate (GDP), sesquiterpenes (C15-based) from the cytoplasmically derived farnesyl diphosphate (FDP) and diterpenes (C20-based) from geranylgeranyl diphosphate, which is also plastid-derived. Although these compounds provide biosynthetic building blocks to various primary metabolites including hormones and photosynthetic pigments, the majority function as secondary metabolites. These improve the ecological fitness of the organism by enabling communication to pollinators and seed dispersal agents and the provision for defense against pathogens and herbivores (2-5). Terpenes can also affect quality traits, including susceptibility to storage disorders, in crops such as apples (6) and pears (7).Divergent TPS share various structural features. These include a highly conserved C-terminal domain, which contains their catalytic site (8) and an aspartate-rich DDXXD motif (9) essential for the divalent metal ion (typically Mg 2ϩ or Mn 2ϩ ) assisted substrate binding in these enzymes (10 -14). This conservation is also shared in their reaction chemistry, which is characterized by electrophilically initiated carbocation formation, carbocation stabilization, and rearrangement, incorporating exquisite regio-a...

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α-Farnesene: Isolation from the natural coating of apples

Cited by 67 publications

References 0 publications

Constituents of Essential Oil ofAframomum giganteum

Constituents of Essential Oil ofAframomum giganteum

Composition of aphid alarm pheromones

Defining the Potassium Binding Region in an Apple Terpene Synthase

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