Evidence indicating a chemical reaction between hydroxylamine and riboflavin.

The observation that hydroxylamine inhibits xanthine oxidase activity through interference with the dehydrogenase portion of the enzyme (1) led us to determine whether hydroxylamine forms a chemical complex with riboflavin or its biological derivatives, riboflavin-5phosphate (FMN) and flavin adenine dinucleotide (FAD). These studies were stimulated by those of Kaplan and his group, who explained hydroxylamine inhibition of alcohol dehydrogenase activity (2, 3) by demonstrating that diphosphopyridine nucleotide (DPN) forms a chemical complex with hydroxylamine (4, 5). Spectrophotometric data reported in this paper indicate the formation of a chemical complex among riboflavin, FMN, FAD, and hydroxylamine.