Funds are requested to purchase a modern, state-of-the-art amino acid analyzer to be located in our Bioanalytical Center. This instrument will replace an outdated Beckman MB121 and will provide essential, more sensitive, quantitative amino acid composition data for a core of 12 users plus a wide range of other biomedically-related scientist at Washington State University and at nearby University of Idaho. Projects to be supported by this instrument include active site studies of photolabeled and photomodified contractile proteins, analysis of chemically modified and affinity labeled enzymes; characterization of endogenous peptides involved in nutrient-induced suppression of foot intake; analysis of a prostaglandin dehydrogenase in lungs and ovaries; investigation of the properties of polypeptides bound to SecB, a molecular chaperone from E coli, analysis of synthetic peptides to be used in studying the physiology and pharmacology of angiotensin receptors; characterization of enzymes and mutant enzymes which catalyze the cyclization of terpenoid substrates; characterization of newly discovered peptide hormones in plants and antigenic sites on viral proteins; quantitation of aromatic amino acids in tumors and serum.