Uridine phosphorylase 1, also known as UPP1 catalyses the reversible phosphorolysis of uridine to uracil. The reaction products are then utilized as carbon and energy sources, or in the rescue of pyrimidine bases for nucleotide synthesis. The expression levels and the enzymatic activity of UPP1 are higher in human solid tumors than in adjacent normal tissues. In addition, UPP1 controls the homeostatic regulation of uridine concentration in plasma and tissues and plays a role in the intracellular activation of 5-fluorouracil. Recombinant human UPP1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.