The synthesis of phosphoenolpyruvate carboxylase in imbibing sorghum seeds.

When sorghum seeds were imbibed either in the light or in the dark, the presence of newly synthesized phosphoenolpyruvate carboxylase (PEPC) could be detected immunologically after approximately 6 h. In addition, both PEPC mRNA and enzyme activity were detected in extracts of dry seeds prior to inhibition. By contrast, ribulose-1,5-bisphosphate carboxylase mRNA, protein, and activity, as well as chlorophyll, were not detected even after 24 h of inhibition. These observations suggest that the nonphotosynthetic form of PEPC is synthesized during seed development and may play an important role in the germinative process.