Involved in the gluconeogenesis. Catalyzes stereospecifically the conversion of dihydroxyacetone phosphate (DHAP) to D-glyceraldehyde-3-phosphate (G3P). D-glyceraldehyde 3-phosphate = dihydroxyacetone phosphate kcat is 4.3 min(-1) for isomerase activity. Optimum pH is 7. Optimum temperature is 37 degrees Celsius. The enzyme is stable up to 50 degrees Celsius. At 55 degrees Celsius, the enzyme retains approximately half of its activity but it is completely inactivated at 60 degrees Celsius. Carbohydrate biosynthesis; gluconeogenesis. Carbohydrate degradation; glycolysis; D-glyceraldehyde 3-phosphate from glycerone phosphate: step 1/1. Homodimer. Belongs to the triosephosphate isomerase family.