METABOLISM OF [4-C-14] LEVULINIC ACID BY ETIOLATED AND GREENING LEAVES OF HORDEUM-VULGARE

When etiolated barley (Hordeum vulgare L. cv. Larker) shoots are incubated with [4-14C]levulinic acid, 14CO2 is evolved, and amino and organic acids are labelled. Respiratory inhibitors and short-chain fatty acids, similar in size to levulinic acid, reduce the production of 14CO2 from [4-14C]levulinic acid, while .delta.-aminolevulinic acid treatment or illuminating the tissue increase 14CO2 evolution. The contribution of levulinic acid metabolism to .delta.-aminolevulinic acid biosynthesis is no greater than that of a general cellular metabolite. The data suggest that fatty acid oxidation and the citric acid cycle are involved in levulinic acid metabolism.