The Distribution of Xanthine Oxidase I

Abstract

Finely divided tissues containing xanthine oxidase very rapidly reduce methylene blue in the presence of hypoxanthine. Tissues which do not contain the enzyme require hrs. under similar conditions to effect the reduction. The reaction is unequivocal and requires so little of the tissue that it may be used to determine the presence or absence of the enzyme. A large number of tissues from a wide variety of species were examined by this technique and the results of previous investigators confirmed. The enzyme is strikingly localized.