Glycerol kinase (GlpK) is a phosphotransferase that is involved in lipolyses, the breakdown of fat stored in fat cells and release of free fatty acids into the bloodstream. GlpK catalyzes the transfer of a phosphate from ATP to glycerol in the presence of Mg2+, thus forming glycerol 3-phosphate and ADP. GlpK has three allosteric effectors with indipendent mechanism: fructose 1,6-bisphosphate (FBP); the phosphocarrier protein IIAGlc; and adenosinemonophosphate (AMP). The product of the reaction, glycerol 3-phospate, may then be converted to dihydroxyacetone phosphate (DHAP) by the enzyme glycerol-3-phosphate dehydrogenase. DHAP can then be rearranged into glyceraldehyde 3-phosphate(GA3P) by triose phosphate isomerase(TIM), and feed into glycolysis. Another important role of the glycerol 3-phosphate is involvement in the glycerol-3-phosphate shuttle, a mechanism used to rapidly regenerate NAD+ in brain and skeletal muscle cells of mammals.
The glycerol is a central component of many lipids most well-known as triglycerides, and glycerophospholipids, or phospholipids, are a major component of all cell membranes.