Bile Salt-Activated Lipase

The presence of a redundant lipolytic system of bile salt-activated lipase (BAL) and pancreatic lipase results in the concerted action of these lipolytic enzymes during intestinal dietary fat digestion processes (1 ). Because of its wide substrate reactivity, BAL is involved not only in the digestion of the major dietary fat, triacylglycerol, but also other important minor dietary lipids such as fat-soluble vitamin esters and cholesterol esters. Because of the nutritional importance of BAL, it is desirable to be able to purify the enzyme for studying its functional properties. Measurements of BAL activity are of interest because they reflect various aspects of enzyme function, such as the regulation of the enzyme activity by bile salt and by its substrates. In this chapter, we summarize the procedure for the assay, purification and expression of human BAL in E. coli .