Metabolism of d-glucuronolactone in mammalian systems. 2. Conversion of d-glucuronolactone into d-glucaric acid by tissue preparations

Abstract

Rat-liver preparations converted D-glucuronolactone into a factor that, after treatment with acid, was a powerful competitive inhibitor of B-gluc-uronidase. Partially purified enzyme preparations required the presence of NAD for this conversion. D-Glucaric acid was isolated from an enzyme digest, and identified as its bisphenylhydrazide. The same enzyme system appeared to be present in liver of other species, including man, and in testis and in rat kidney. The mechanism of the reaction, and its implication in L-ascorbic acid biosynthesis, are discussed. The name "D-glucuronolactone dehydrogenase" has been given provisionally to this enzyme.