Figure 3.

Effect of cotyledon development on MCCase activity and Leu, protein, and chlorophyll accumulation. A, Chlorophyll and total protein contents. B, MCCase activity and free Leu content. C, Western blot probed with antiserum to detect the biotin-containing subunit of MCCase. D, Western blot identical to that shown in C, but instead probed with ¹²⁵I-streptavidin to detect the biotin prosthetic group on the biotin-containing subunit of MCCase. In C and D protein samples were loaded on the basis of equal MCCase activity (0.1 nmol/min) to detect differences in the catalytic efficiency of the enzyme during cotyledon development. The data presented in A and B are means ± se from three replicates. The data presented in C and D were gathered from a single experiment; three replicates of this experiment gave similar results.