Bile salt-activated lipase (BSAL) is found in the milk of a limited number of mammals: humans, gorillas, dogs, and cats. The enzyme plays an important role in the infant diet in the digestion of lipids and, as such, effects a striking quantitative difference between breast-fed and formula-fed infants in weight gain; in this regard, it is important to note that BSAL is absent in bovine milk. In Phase IB research, we plan to clone, sequence and express the cDNA for human BSAL and provide a framework for Phase II research wherein recombinant human BSAL will be produced in large quantities for supplementation in infant formulas. Expression of the human BSAL cDNA will be achieved by cloning into an expression vector suitable for production at high levels in Saccharomyces cerevisiae. Levels of expression will be ascertained by ELISA and direct measurements of enzymatic activity. The recombinant protein will be purified and characterized for its physical and chemical similarity to the purified human milk enzyme.
