Abstract
Both glyoxylate reductase (NADP+) and glycollate dehydrogenase were located exclusively in mitochondria in Euglena gracilis and constitute the glycollate–glyoxylate shuttle, whose existence in higher plants was thought doubtful, owing to different subcellular locations of the two enzymes. Disrupted Euglena mitochondria showed a glycollate-dependent NADPH oxidation, indicating actual operation of the shuttle in this protozoon.