Publisher Summary This chapter presents an overview of glyceride digestion and discusses the specific enzymes known to be involved in glyceride digestion. Naturally occurring glycerides are esters of long-chain fatty acids and glycerol. The chapter describes the properties of the various enzymes that play a role in the intraluminal digestion of glycerides. An anatomical order is followed beginning with milk lipases, then preduodenal lipase, and finally pancreatic lipases. Human milk contains two lipolytic enzymes—namely, lipoprotein lipase, which is shed from the endothelial cells of the mammary gland, and a bile-salt-stimulated lipase. The lipoprotein lipase is identical to that found in other sources of the enzyme and probably does not play an important role in milk–fat digestion. Bile-salt-stimulated lipase hydrolyzes all three ester bonds in a triglyceride. With emulsions of long-chain triglycerides as substrate, bile salts are required for hydrolysis. Most of the work on pancreatic lipase has been conducted with lipase from porcine pancreas, which is a very rich source for the enzyme. The purification of the porcine enzyme yields two forms of the enzyme, which differ in carbohydrate content. This preparation is contaminated by colipase, and a further purification step is required to obtain colipase-free lipase. This lipase has also been purified from rat, ox, sheep, horse, and human pancreas. The porcine enzyme is composed of a single polypeptide chain containing 449 amino acids with a molecular weight of 49,900, which agrees with several measurements by various physical methods.