Isolation of uridine 5'-pyrophosphate glucuronic Acid pyrophosphorylase and its assay using p-pyrophosphate

A procedure was devised to detect and assay uridine 5'-pyrophosphate (UDP)-glucuronic acid pyrophosphorylase in plant extracts. Substrates are UDP-glucuronic acid and (32)P-pyrophosphate, and the (32)P-uridine 5'-triphosphate produced is selectively adsorbed to charcoal. The charcoal adsorption procedure is a modification of that used to determine (32)P-adenosine 5'-triphosphate produced by adenosine 5'-pyrophosphate glucose pyrophosphorylase, and the modification greatly improves the retention of uridine 5'-triphosphate.