The enzymic and non-enzymic degradation of colneleic acid, an unsaturated fatty acid ether intermediate in the lipoxygenase pathway of linoleic acid oxidation in potato (Solanum tuberosum) tubers

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Abstract
Colneleic acid is an unsaturated ether fatty acid derived from linoleic acid via a lipoxygenase-mediated enzyme pathway. It is degraded (a) by an enzyme in potato tubers which is heat-labile and non-dialysable and (b) by a model system containing catalytic amounts of Fe2+ ions. Both enzyme- and Fe2+-catalysed systems have similar properties with respect to pH optima (pH5.0–5.5), oxygen requirement (0.6–0.7 mol of O2 consumed/mol of ether degraded), inhibitors and reaction products. An unstable product breaks down to C8 and C9 carbonyl fragments. Both systems are inhibited by low concentrations of antioxidants (e.g. 5μm-butylated hydroxytoluene) and some chelating agents (e.g. 5μm-diethyldithio-carbamate). The model system is strongly inhibited by metal ions, particularly Cu2+ and Fe3+, at 20μm. Hydrogen peroxide and haemoproteins do not substitute for the enzyme or Fe2+ ions but the non-haem iron protein, ferredoxin, does catalyse the degradation.