Xanthopterin Obtained from the Skins of the Yellow Mutant of Bombyx mori (Silkworm)

Abstract

Boiling water-extracts of the lipochrome-freed skins of 100 yellow mutant (lem) 5th instar silkworm larvae contain uric acid, xanthopterin, and a white crystalline compound, related to but not identical with isoxanthopterin or leucopterin, which compound is probably a new pterin. This new pterin is obtained in greater amts. from the skins of the normal type of larvae. Xanthopterin is identified by fluorescence and paper chromatography using extract of the wings of the pierid Eurema etaeta, known to contain xanthopterin, as a standard.