Hormone-sensitive lipase (HSL) has a major role in fatty acid mobilization from adipose tissue by catalyzing the rate-limiting step in the lipolysis of stored triacylglycerols. From previous work with adipose tissue preparations, fast-acting lipolytic hormones were generally thought to control HSL through cyclic AMP-mediated phosphorylation of the enzyme. This chapter summarizes the molecular mechanisms for short-term hormonal control of the enzyme in adipose tissue and other organs and emphasizes the current state of knowledge and the progress as the result of identification, purification, and characterization of HSL. HSL is inhibited by micromolar concentrations of diisopropyl fluorophosphate (DFP) and the inhibition is parallelled by [3H]DFP incorporation into the enzyme, indicating that a reactive serine residue is involved in its catalytic function. HSL has broad substrate specificity, hydrolyzing long-chain tri-, di-, and monoacylglycerols, as well as cholesterol esters. In several aspects, HSL is similar to other tissue lipases, such as lipoprotein lipase and hepatic lipase. However, the relatively higher diacylglycerol lipase activity and, in particular, the ability to hydrolyze cholesterol esters distinguish HSL from these lipases. Cyclic adenosine monophosphate (AMP)-dependent protein kinase phosphorylates HSL at a single serine residue in a site termed as “the “regulatory phosphorylation site,” which can be found in a proteolytic peptide of about ten amino acid residues. © 1987, Academic Press Inc.
Strålfors, P., Olsson, H., & Belfrage, P. (1987). Hormone-Sensitive Lipase. Enzymes, 18(C), 147–177. https://doi.org/10.1016/S1874-6047(08)60257-7