Important as a means of generating NADPH for biosynthetic reactions. D-glyceraldehyde 3-phosphate + H2O + NADP(+) = (2R)-3-phosphoglycerate + 2 H(+) + NADPH Insensitive to magnesium or calcium when dephosphorylated. When phosphorylated, 3-fold activation by magnesium or calcium, 2-fold activation by potassium, inhibited by ADP and AMP and insensitive to ATP or PPi. When the protein is phosphorylated, the affinity for substrates is similar but the Vmax is lowered. Interacts with 14-3-3 protein when phosphorylated. This interaction is released by divalent cations. Phosphorylated in shoots and non-photosynthetic tissues, but not in leaves. Belongs to the aldehyde dehydrogenase family. Sequences of mRNA encoded by the same gene but extracted from leaves (AF521191) or from endosperm (AF521190) differ at several prositions due to sequencing uncertainties.