Occurrence and Biosynthesis of Glyoxysomal Enzymes in Ripening Cucumber Seeds

Abstract

Glyoxysomal enzymes, necessary during seed germination, are synthesized at the stage of seed maturation. Two stages of embryogenesis of cucumber seeds (C. sativus) were investigated. One was characterized by the presence of microbodies showing catalase and enoyl-CoA hydratase activities. Microbodies at a later stage also contained malate synthase and isocitrate lyase. The biosynthesis of 3 microbody components was followed in a pulse chase-labeling experiment which demonstrated that the biosynthesis of cytosolic species of malate synthase, isocitrate lyase and enoyl-CoA hydratase preceded the appearance of these proteins in microbodies.