Biochemical differences between the mutants Rosy-2 and maroon-like of Drosophila melanogaster.

HE conversion of 2-amino-4-hydroxypteridine into isoxanthopterin in wildtype Drosophila melanogaster has been demonstrated and investigated by several groups (FORREST, GLASSMAN and MITCHELL 1956; HADORN and SCHWINCK 1956; NAWA, TAIRA and SAKAGUCHI 1958). This reaction is catalyzed by an enzyme which will also catalyze the oxidation of hypoxanthine through xanthine into uric acid, xanthopterin into leucopterin (Figure 1 ), and benzaldehyde into benzoic acid, all of these being typical xanthine oxidase catalyzed reactions. However, the enzyme from Drosophila requires an electron acceptor, presumed to be diphosphopyridine nucleotide (DPN) , in the living organism and has therefore been called a xanthine dehydrogenase (GLASSMAN and MITCHELL 1959a).