UV-Absorbing and UV-Fluorescing Substances in the Belly Skin of Fry of Coho Salmon (Oncorhynchus kisutch)

Abstract

The belly skin of 4-month-old coho salmon fry was extracted with 0.5 M NH₄OH, and the extract was analyzed by paper chromatography for UV-absorbing and UV-fluorescing substances. Six fluorescing and three absorbing substances were isolated and characterized by R_fvalues, UV-absorption spectra, and chemical reactions, and were identified with known compounds where possible. The three UV-absorbing substances were identified as guanine, hypoxanthine, and inosine monophosphate. Three of the UV-fluorescing substances were identified as ichthyopterin, pterin 6-carboxylic acid, and 7,8-dihydroxanthopterin. A fourth fluorescing substance appeared to be an artefact produced by the action of NH₄OH on ichthyopterin. The remaining two fluorescing substances appeared to be unknown glycosides, presumably isomers, both containing glucose, xylose, and mannose.