DHAP

Dihydroxyacetone phosphate (DHAP) is a phosphorylated three-carbon sugar intermediate in metabolism. It is produced during glycolysis from fructose-1,6-bisphosphate by the action of aldolase, which cleaves the molecule into DHAP and glyceraldehyde-3-phosphate (GAP). DHAP is rapidly interconverted with GAP by the enzyme triose phosphate isomerase, allowing glycolytic flux to proceed through either isomer depending on cellular needs.

DHAP serves several metabolic roles. It can be reduced to glycerol-3-phosphate by cytosolic glycerol-3-phosphate dehydrogenase, using NADH. Glycerol-3-phosphate is a key backbone for the synthesis of triglycerides and phospholipids, linking carbohydrate metabolism to lipid biosynthesis. DHAP is also involved in the glycerol-3-phosphate shuttle, which transfers reducing equivalents from cytosolic NADH into mitochondria for oxidative phosphorylation.

Physiologically, DHAP and its interconversion with GAP help regulate glycolysis and lipogenesis in tissues such as liver and adipose tissue. The balance between DHAP and GAP can influence the distribution of glucose-derived carbon between energy production and lipid synthesis.

Clinical and research notes: defects in triose phosphate isomerase or disruptions of the glycolytic pathway can disturb DHAP and GAP pools, contributing to metabolic disorders and impaired energy metabolism. In biochemistry and physiology research, DHAP is used as a substrate in various enzyme assays and as a tracer in studies of carbohydrate and lipid metabolism.

Overall, DHAP is a key metabolic intermediate that links glycolysis to lipid biosynthesis and energy transfer through cellular shuttle systems.