The effect of light on xanthine oxidase activity

Abstract
Contrary to the results of Bernheim and Dixon (Biochem. Jour. 22: 113. 1928) no evidence could be obtained of an activation of xanthine oxidase by light. It is suggested that the apparent activation observed by Bernheim and Dixon was of an indirect nature and may have been due to photodehydrogenation of impurities in their prepn., with concomitant reduction of the methylene blue employed as H acceptor.