The goal of this research is to study the mechanism of peptide transport in human small intestine using brush border membrane vesicles. Presently, there is no information on the specificity and multiplicity of the peptide transport systems located on human small intestine. The specific aims are: 1. To determine total uptake of the peptide substrate. 2. To investigate the kinetics of peptide transport. 3. To classify the structural characteristics of the peptide transporter. The investigator proposes to conduct a series of experiments starting with the isolation of the human intestinal brush border membrane vesicles obtained from organ donations. Uptake of labeled substrates will be determined by the rapid filtration method and hydrolysis of the peptides will be monitored using high performance liquid chromatography. The simple diffusion component of the peptides will be determined by treating each peptide as a competitive inhibitor of its own mediated transport. Experiments will be conducted to determine the kinetic characteristics of peptide uptake. Various dipeptides and tripeptides will be used as inhibitors in order to determine the specificity of transport.
