A SIMPLIFIED PREPARATION METHOD OF P³²- LABELED FLAVIN MONONUCLEOTIDE AND FLAVIN-ADENINE DINUCLEOTIDE AND THEIR APPLICATION TO BIOCHEMICAL RESEARCHES

Abstract

A simple preparation method of P³²-labeled FAD following injection of P³²-phosphate and FMN in rabbits was investigated. Hydrolysis of P³²-FAD thus obtained results in the production of P³²-FMN. In this case the phosphor of FMN has probably been exchanged for P³². It can be understood by the reversibility of the reaction: Riboflavin+PO₄^3-⇔FMN. Although the ratio of incorporation of P³² into FAD is very low, the radioactivity of the P³²-FAD thus obtained is strong enough to be used for biochemical experiments. The P³²-FMN obtained from P³²-FAD was utilized for investigation of riboflavin metabolism in vivo and the mechanism of riboflavin photolysis.