Involved in the gluconeogenesis. Catalyzes the oxidative phosphorylation of glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (BPG) using the cofactor NADP. The first reaction step involves the formation of a hemiacetal intermediate between G3P and a cysteine residue, and this hemiacetal intermediate is then oxidized to a thioester, with concomitant reduction of NADP to NADPH. The reduced NADPH is then exchanged with the second NADP, and the thioester is attacked by a nucleophilic inorganic phosphate to produce BPG. D-glyceraldehyde 3-phosphate + NADP(+) + phosphate = (2R)-3-phospho-glyceroyl phosphate + H(+) + NADPH D-glyceraldehyde 3-phosphate + NAD(+) + phosphate = (2R)-3-phospho-glyceroyl phosphate + H(+) + NADH kcat is 1 sec(-1) for dehydrogenase activity with NAD (at pH 9.2 and 25 degrees Celsius). kcat is 8 sec(-1) for dehydrogenase activity with NADP (at pH 9.2 and 25 degrees Celsius). Carbohydrate biosynthesis; gluconeogenesis. Homotetramer (By similarity). Interacts with BrxC (PubMed:33722570). In response to oxidative stress, the active site Cys likely reacts with bacillithiol (BSH) to form mixed disulfides to protect the Cys residue against overoxidation. S-bacillithiolation presumably leads to loss of catalytic activity. Debacillithiolation by monothiol bacilliredoxin BrxC restores the activity. Cells lacking this gene are unable to grow in medium containing asparagine as a sole carbon source but presents the same growth rate as the wild-type in glucose-containing medium. Belongs to the glyceraldehyde-3-phosphate dehydrogenase family.