title: Localization of Enzymes of Glycolate Metabolism in the Alga Chlorogonium elongatum.
abstract: Organelles in homogenates from autotrophic cells of Chlorogonium elongatum were separated on linear sucrose gradients. The distribution of enzymes typical of leaf peroxisomes was determined.Whereas more than 60% of the catalase activity was particulate and recovered in microbodies at a mean density of 1.225 g/cm(3) within the gradient, in most experiments only 5 to 10% (as a maximum 30%) of the NAD-dependent hydroxypyruvate reductase was particulate, and this was recovered principally at density 1.19 g/cm(3). This distribution coincides with that of cytochrome oxidase, malate dehydrogenase, and isocitrate dehydrogenase, the mitochondrial markers. Glyoxylate-glutamate aminotransferase and glycolate dehydrogenase showed a similar distribution pattern to that of NAD-dependent hydroxypyruvate reductase. Thus in Chlorogonium the enzymes of the glycolate pathway are not associated with the microbodies that are recovered at density 1.225 g/cm(3).The single large chloroplasts of the Chlorogonium cells are broken during grinding, and this probably accounts for the finding that NADP-glyoxylate reductase was recovered only in the soluble fractions of the gradient.
authors: Division of Natural Sciences, University of California, Santa Cruz, California 95064.
authors: H
authors: H
authors: Stabenau