Gliserol3fosfata

Gliserol-3-fosfata, also known as glycerol-3-phosphate (G3P), is a phosphorylated derivative of glycerol that serves as a central metabolic intermediate in many organisms. It functions as a link between carbohydrate and lipid metabolism and exists in multiple cellular pools and redox states, depending on the cellular environment.

Biosynthesis and interconversion occur through several pathways. In mammals, glycerol kinase converts glycerol to glycerol-3-phosphate using ATP, providing a substrate for triglyceride and phospholipid synthesis. In glycolytic metabolism, dihydroxyacetone phosphate (DHAP) can be reduced to glycerol-3-phosphate by cytosolic glycerol-3-phosphate dehydrogenase, using NADH. In mitochondria, glycerol-3-phosphate dehydrogenase participates in the glycerol phosphate shuttle, oxidizing G3P back to DHAP and transferring electrons to the electron transport chain via FAD.

Function and significance extend to lipid biosynthesis and energy metabolism. G3P serves as the glycerol backbone for the synthesis of glycerophospholipids and triglycerides; sequential acylation of G3P yields phosphatidic acid, a key intermediate in membrane lipid and storage lipid production. The glycerol phosphate shuttle helps maintain cytosolic redox balance by exporting reducing equivalents to the mitochondria.

Distribution and variation occur across organisms, including bacteria, plants, yeast, and animals, with cytosolic and mitochondrial forms contributing to species- and tissue-specific metabolic needs. Proper regulation of G3P levels is important for lipid homeostasis and energy metabolism, and disruptions can be linked to metabolic disorders in some contexts.