Preparation of [14C]uridine 5'-diphosphate and [14C]guanosine 5'-diphosphate

Procedures have been developed for the routine enzymatic synthesis of [14C]UDP and [14C]GDP from commercially available enzymes and [14C]UMP and [14C]GMP. Using high pressure liquid chromatography, the products are recovered in high yield (60-80%) and with high purity. The [14C]UDP and [14C]GDP are utilized as substrates for ribonucleotide reductase.