Photometabolism of Glycollate by Euglena Gracilis

Abstract

The photometabolism of glycollate was investigated in E. gracilis, strain Z, an organism which can utilize glycollate as a single source of carbon in the light but not in the dark. The nature of the labelled products of the photometabolism of [1-14CJglycollate, [2_14CJglycollate, and [l-14CJglycine and the inhibition of growth on glycollate by isonicotinyl hydrazide and by ex-hydroxy-2-pyridine methane sul-phonate were consistent with the operation of a glycollate pathway of the type found in the leaves of higher plants. In addition, several enzymes associated with gly-collate metabolism in other photosynthetic organisms were demonstrated in cell-free extracts of E. gracilis grown with glycollate as the only carbon source. These included glycollate oxidase, NADPH: glyoxylate reductase, NADH: glyoxylate reductase (E.C.1.1.1.26), glycine transaminase (E.C.2.6.1.4), formyltetrahydro-folate synthetase (E.C. 6.3.4.3), and serine hydroxymethyltransferase (E.C. 2.1.2.1).