Cytochemical localization of catalase activity in glyoxysomes from castor bean endosperm

Glyoxysomes isolated from castor bean (Ricinus communis L. var. zanzibariensis) endosperm have been stained by the cytochemical diaminobenzidine reaction. The reaction product obtained by preincubation with 3,3'-diaminobenzidine and incubation with the reagent and H(2)O(2) is distributed uniformly throughout the matrix of the organelles. Ricinosomes or dilated cisternae may be completely absent from the organelle preparation or are, at the most, a minor contaminant.