Characterization of Transcriptional Control Elements in the Mammary Gland and Pancreas: Studies of the Carboxyl Ester Lipase Gene

Abstract

The human lactating mammary gland synthesizes and secretes with the milk a bile saltstimulated lipase (BSSL) that, after specific activation by primary bile salts, contributes to the breast-fed infant’s endogenous capacity for intestinal fat digestion. This enzyme, which accounts for approximately 1% of total milk protein, is a very nonspecific lipase. BSSL is not degraded during passage with the milk through the stomach. It is, however, inactivated when the milk is pasteurized. Our group has isolated a 2359 nucleotide (nt) cDNA clone from human lactating mammary gland and deduced from this, the BSSL enzyme consists of 745 amino acid (aa) residues including a 23 aa leader peptide. We have also isolated and analysed the human BSSL gene, which proved to span a region of 9832 nt and contains 11 exons, see Figure 1. The carboxyl ester lipase (CEL) of human pancreatic juice is a product of the same gene. Because of this, the BSSL gene now is called CEL.