Hydrolysis of flavin adenine dinucleotide and flavin mononucleotide by rabbit blood

Hydrolysis of FAD and FMN by rabbit blood was studied. The whole blood hydrolyzed both FAD and FMN to riboflavin. Blood plasma hydrolyzed FAD rapidly to FMN, but hydrolyzed FMN slowly to riboflavin. On the other hand, red cells hydrolyzed FAD slowly to FMN, but hydrolyzed FMN rapidly to riboflavin. These facts are explained by the localization of respective enzymes in blood plasma and cells.