Biosynthesis of R-(+)-octane-1,3-diol. Crucial role of beta-oxidation in the enantioselective generation of 1,3-diols in stored apples.
The biosynthesis of R-octane-1,3-diol and R-5(Z)-octene-1,3-diol, two natural antimicrobial agents in apples and pears, was investigated in stored apples after application of [9,10,12,13-3H]linoleic acid, [9,10,12,13,15,16-3H]linolenic acid, [1-14C]linoleic acid, [U-14C]oleic acid, lipoxygenase-derived metabolites of [9,10,12,13-3H]linoleic acid, 13C18-labeled linoleic acid hydroperoxides, and 2H-labeled octanol derivatives. Analysis of the products and quantification of incorporation and labeling pattern were achieved by high-performance liquid chromatography-radiodetection, capillary gas chromatography (GC)-isotope ratio mass spectrometry, and GC-mass spectrometry analysis. Almost all the applied precursors were partly transformed into R-octane-1,3-diol. Linoleic acid derivatives, still containing the 12,13 cis double bond, and octanol derivatives oxy-functionalized at carbon 3 were the most efficient precursors of the 1,3-diol. The data imply that R-octane-1,3-diol is generated in stored apples in the course of the beta-oxidation from R-3-hydroxy-octanoyl-SCoA originating from 2-cis-octenoyl-SCoA by enoyl-CoA hydratase. In an analogous fashion, R-5(Z)-octene-1,3-diol is formed from the unsaturated intermediate.
Beuerle
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Lehrstuhl für Lebensmittelchemie, Universität Würzburg, Germany.
Schwab
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D002250:Carbon Radioisotopes; D005638:Fruit / Q000378:metabolism*; D006018:Glycols / Q000138:chemical synthesis* / Q000737:chemistry; D008041:Linoleic Acids / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D013237:Stereoisomerism
D002250:Carbon Radioisotopes; D006018:Glycols; D008041:Linoleic Acids; C400978:octane-1,3-diol