The objective of this project is to broaden the theoretical and empirical bases for understanding receptor-substrate interactions in aqueous media. Most important biological processes (immune response, enzymic catalysis, cell transport, nucleic acid replication) involve non-covalent binding between organic molecules. This phenomenon is to be investigated in sophisticated model systems. To accomplish this, general strategies for the synthesis of artificial receptors will be developed. The syntheses are designed to be short and efficient, so that variations on the receptor structure may be easily made and the effect of structure on the receptor-substrate interactions can be thoroughly evaluated. Quantitative measurements of association constants for specific pairs of synthetic receptors and substrates will be determined by spectrophotometric measurement. Comparisons of measured association constants and predicted free energies of interaction will be made. In this way available computational methods for quantifying receptor-substrate interactions can be refined. The potential technological applications of the knowledge gained in this project are exciting and diverse.