D-glyceraldehyde 3-phosphate = dihydroxyacetone phosphate Carbohydrate biosynthesis; gluconeogenesis. Carbohydrate degradation; glycolysis; D-glyceraldehyde 3-phosphate from glycerone phosphate: step 1/1. Homodimer. In plants, there are two types of TPIS, cytosolic and plastid. Belongs to the triosephosphate isomerase family. Was originally thought to be (S)-tetrahydro-berberine oxidase (EC 1.3.3.8).