Studies on the Development and Localization of Catalase and H(2)O(2)-generating Oxidases in the Endosperm of Germinating Castor Beans

During germination of castor bean seeds (Ricinus communis var. Hale), the changes of activity of catalase, uricase, and α-hydroxyacid oxidase of the endosperm follow a rise and fall pattern with a peak between day 4 and 5 similar to that observed for the glyoxylate cycle enzymes. After 3 days of germination, most of the activities of these enzymes are recovered from the glyoxysomal fraction separated by isopycnic sucrose density gradient centrifugation.