Peroxisomes in the Alga Vaucheria are Neither of the Leaf Peroxisomal Nor of the Glyoxysomal Type*,1

Microbodies were isolated from the freshwater alga Vaucheria sessilis as well as from a marine Vaucheria. The organelles equilibrated on sucrose gradients at densities 1.23 g . cm^?3 and 1.24g . cm^?3, respectively. On electron micrographs they showed an ovoid or spheroid shape with a diameter of 0.5 to 0.8 μm. Besides catalase, the peroxisomes of both algae possess glycolate oxidase and glutamate-glyoxylate aminotransferase, but no other leaf-peroxisomal enzymes. Instead, the enzymes malate synthase and isocitrate lyase, which are markers of glyoxysomes in higher plants, are constituents of the peroxisomes in the marine as well as in the freshwater alga. Citrate synthase, aconitase, malate dehydrogenase and enzymes of the fatty acid β-oxidation pathway are located exclusively in the mitochondria. Therefore, the peroxisomes from Vaucheria do not belong to either the type of leaf peroxisomes or to the type of glyoxysomes.