The aim of this proposal is to acquire a medium resolution mass spectrometer equipped with electron-impact, chemical ionization, and fast-atom bombardment ion sources and interfaced to a gas chromatograph and a data acquisition and processing system to support the research of three current NIH grantees at the University of Hawaii. The instrument will be used primarily for four areas of research: (1) for structural analysis and identification of pharmacologically active natural products, in particular anticancer drugs isolated from marine organisms and cultured blue-green algae; (2) for structural studies of the binding site of the visual pigment and related vitamin A binding proteins; (3) for characterization of intermediates in the total synthesis of pharmacologically active natural products; and (4) for structural studies of the binding site of the phorbol ester receptor.