Monoacylglycerol lipase is an enzyme that hydrolyzes a fatty acid from a monoacylglycerol (glycerol with one fatty acid esterified to it) to yield glycerol and a free fatty acid. Monoacylglycerols arise from action of diacylglycerol lipase on a diacylglycerol, which hydrolyzes one of the two fatty acids from it. Further digestion of the monoacylglycerol requires the action of monoacylglycerol lipase.