Glycerol3Phosphate

Glycerol-3-phosphate, also known as sn-glycerol-3-phosphate, is the phosphorylated derivative of glycerol in which a phosphate group is esterified to the third carbon of the glycerol backbone. It exists as two enantiomers in biological systems, typically referred to as the D- and L- forms, with the active stereoisomeric forms varying among organisms.

Biogenesis and metabolism: Glycerol-3-phosphate can be formed from dihydroxyacetone phosphate (DHAP) by glycerol-3-phosphate dehydrogenase, a reaction linked to cellular redox state via NADH. It can also be produced from glycerol by glycerol kinase, using ATP. The molecule can be oxidized back to DHAP by mitochondrial glycerol-3-phosphate dehydrogenase, a step that participates in the glycerol phosphate shuttle to transfer reducing equivalents from cytosol to mitochondria.

Role in lipid biosynthesis: Glycerol-3-phosphate serves as the backbone for glycerophospholipid synthesis. Acyltransferases first convert G3P to lysophosphatidic acid and then to phosphatidic acid, a central intermediate that can be exported to form diacylglycerol and subsequently various phospholipids or triglycerides.

Biological significance: Glycerol-3-phosphate is a key metabolic intermediate in both glycolysis and lipid metabolism. In bacteria, its production and utilization are essential for phospholipid biosynthesis, while in eukaryotes it participates in cellular energy balance and membrane lipid formation.