Free radical-producing enzyme, xanthine oxidase, is undetectable in human hearts

1 September 1987

journal article
research article
Published by American Physiological Society in American Journal of Physiology-Heart and Circulatory Physiology

Vol. 253 (3) , H709-H711
https://doi.org/10.1152/ajpheart.1987.253.3.h709

Abstract

Samples from four human hearts were analyzed for both their xanthine dehydrogenase and xanthine oxidase content. We used the conventional spectrophotometric assay and a more sensitive fluorometric assay to determine the content of enzyme in these samples. In no case could any activity be detected. We conclude that human hearts must contain less than 2.0 nU/g of activity. This makes it unlikely that xanthine oxidase is a significant source of O2 free radicals in the ischemic human heart or that xanthine oxidase inhibitors will be of therapeutic value in that setting.