What enzyme is responsible for converting glycerol to glycerol-3-phosphate in the liver for triglyceride synthesis?

Glycerol kinase is the enzyme responsible for converting glycerol to glycerol-3-phosphate in the liver, which is a critical step in triglyceride synthesis. This reaction is important because triglycerides are formed from glycerol and fatty acids through esterification. In the liver, glycerol derived from the breakdown of triglycerides can enter glycolysis or be used for gluconeogenesis, but to be utilized for triglyceride synthesis, it must be first phosphorylated to glycerol-3-phosphate.

Glycerol kinase catalyzes the phosphorylation of glycerol, using ATP as a phosphate donor, resulting in glycerol-3-phosphate. This compound acts as a backbone to which fatty acids are attached, leading to the formation of triglycerides in adipose tissue as well as the liver.

The other enzymes listed do not directly catalyze this specific conversion. Phospholipase A2 is involved in the hydrolysis of phospholipids, acyl-CoA synthetase activates fatty acids by converting them to acyl-CoA, and lipase is involved in the breakdown of triglycerides into free fatty acids and glycerol. Thus, glycerol kinase is the unique enzyme that specifically catalyzes the initial step in the conversion