Albumins, glyoxysomal enzymes and globulins in dry seeds of cucumis sativus: qualitative and quantitative analysis.

1. Albumins and globulins were prepared from dry seeds of cucumbers (Cucumis sativus) by differential extraction. The globulin fraction was analyzed by gel electrophoresis under denaturing conditions in the presence and absence of mercaptoethanol. The subunit (Mr = 54000) of the tetramer (Mr = 240000) was shown to be composed of two different peptides. Microheterogeneity rendered the exact interpretation of the analysis difficult. 2) Glyoxysomal proteins were already present in dry seeds: malate synthase, isocitrate lyase, citrate synthase, malate dehydrogenase, catalase and crotonase could be detected unequivocally. It was demonstrated that the enzymatic and immunological properties of malate synthase and isocitrate lyase were not distinguishable from that of enzymes assigned to glyoxysomes of fully developed cotyledons. 3) Homogenates prepared from seeds by cautious cell disintegration were subjected to sucrose density gradient centrifugation and yielded microbody and protein body fractions, among other things.