A second project deals with the synthesis of Atrial Natriuretic Factor (ANF) and its interaction with nucleotides. ANF is a 28-amino acid peptide with one disulfide bond; it is a peptide hormone that is produced by the atrium of the heart and is circulated throughout the body to regulate blood pressure. Its main biological function is directed toward natriuresis and diuresis, and smooth muscle relaxation, resulting in lowering blood pressure. The cellular response of lowering blood pressure is a cascade of events (signal transduction) initiated by ANF binding to the extracellular domain of the receptor protein. We are interested in the mechanism of action of ANF that leads to the signal transduction mediated by ANF. Thus, it is important to determine the bioactive conformation of ANF and to sort out mechanistic steps that emanate the actions of ANF. We are studying the ANF-nucleotide interaction as a part of this mechanism. Mass spectrometry (MALDI-MS) is used to determine the molecular weight of the synthesized peptide; and NMR spectroscopy is for investigating the ANF-nucleotide binding.