A purified novel enzyme protein, UGPPase, which naturally occurs in animal cells, its productions of recombinant technology, an antibody to the enzyme protein, a method of carrying out ELISA for measurement of the amount of UGPPase in an analyte and a method for determination of UDPG in a sample. The one-way enzyme protein catalyses hydrolysis of UDP-glucose, the precursor molecule of glycogen, into glucose-1-phosphate (G1P) and uridine 5′-monophosphate (UMP).