Gly3P is formed from glycerol by ATP-dependent phosphorylation catalyzed by glycerol kinase.

Glycerol + ATP <=> Gly3P + ADP

Gly3P is an important part of glycerol metabolism. Glycerol is generated by digestion of fats. Conversion of Gly3P to DHAP by the enzyme glycerol-3-phosphate dehydrogenase adds glycerol's carbon backbone to the glycolysis or gluconeogenic pathways.