Abstract
Experiments on the phosphorylation were made with homogenate, mitochondria suspension fluid and supernatant fluid, all added with riboflavin, of various organs and the blood, using normal rabbits, normal and riboflavin-deficient mice. Phosphorylation of riboflavin was observed in livers, kidneys and small intestines of rabbits and mice and in the chicken blood. It took place in the mitochondria. Although, in small intestines, FMN alone was synthesized from riboflavin, the synthesis of FAD from riboflavin could be found in liver and kidneys. In small intestines glucose-1-phosphate, besides ATP, acted as a phosphate-donor.
