A lipase (/ˈlaɪpeɪs/, /ˈlɪpeɪs/, /-peɪz/) is any enzyme that catalyzes the hydrolysis of fats (lipids). Lipases are a subclass of the esterases.
Lipases perform essential roles in the digestion, transport and processing of dietary lipids (e.g. triglycerides, fats, oils) in most, if not all, living organisms. Genes encoding lipases are even present in certain viruses.
Most lipases act at a specific position on the glycerol backbone of a lipid substrate (A1, A2 or A3)(small intestine). For example, human pancreatic lipase (HPL), which is the main enzyme that breaks down dietary fats in the human digestive system, converts triglyceride substrates found in ingested oils to monoglycerides and two fatty acids.