Changes in glyceraldehyde phosphate dehydrogenase during the life cycle of a green plant

Abstract

The pyridine nucleotide dependence of glyceraldehyde 3-phosphate dehydrogenase (GPD) was investigated throughout the life cycle of pea plants. The GPD of seeds and seedlings germinated in the dark was DPN-specific. In seedlings exposed to light, there appeared after the tenth day, a TPN-linked GPD. This new species of GPD was localized in the green shoot and was absent from roots. Seedlings germinated in the dark developed the TPN-linked GPD upon transfer to light. The light-induced TPN-linked GPD disappeared from the newly formed seed. In the life cycle of the plant from seed to seed, the GPD changes cyclically from obligate DPN dependence in the seed, to a multicomponent system in the shoot, functional with either DPN or TPN, and back to obligate DPN dependence in the newly formed seed.