Studies on the Combined and Relative Influence of Dietary Protein and Riboflavin in Flavoprotein Enzymes

Abstract
Xanthine oxidase and D-amino acid oxidase activities were determined in the livers of 8 groups of rats with 5, 18, 40 and 60% of devitaminized casein with and without added riboflavin. Both xanthine oxidase and D-amino acid oxidase activities of rat liver were reduced to the minimum in a combined deficiency of dietary protein and riboflavin. Xanthine oxidase activity depended much more upon protein (casein) than upon riboflavin, whereas D-amino acid oxidase activity depended more upon riboflavin than upon protein.