Lipase

Abstract

This chapter elaborates the preparation and stability of lipase. Titrimetric methods and other non-colorimetric methods available for the assay of serum lipase differ in their respective substrates. Assay of lipase in the presence of large amounts of other esterases requires a relatively specific system and activation of lipase by bile salts is especially important in making the distinction. Tributyrin and Tween, and even the natural substrate, olive oil, are relatively unspecific and are therefore unsuitable as substrates. It is found that out of the phenol and naphthol esters, 2-naphthyl nonanoate is the most sensitive. It was noted that taurocholate was not a reliable activator of pancreatic lipase in human serum. Substitution of esterase-resistant 2-naphthyl myristate for 2-naphthyl laurate and sodium cholate for sodium taurocholate resulted in a serum method useful in the diagnosis of human pancreatitis. Lipase and esterase hydrolyse 2-naphthyl myristate to 2-naphthol and myristic acid. In the absence of sodium cholate, the slight hydrolysis that occurs is because of esterase, while in the presence of cholate the hydrolysis is almost entirely because of lipase and very little to esterase.