thymidine phosphorylase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: thymidine + phosphate = thymine + 2-deoxy-D-ribose 1-phosphate. [RHEA:16037]

Thymidine phosphorylase (TP) is an enzyme that catalyzes the reversible phosphorolysis of thymidine to thymine and deoxyribose-1-phosphate. This reaction plays a crucial role in the salvage pathway for pyrimidine bases, which is essential for DNA synthesis and repair. TP is also involved in the degradation of thymidine, a nucleoside found in DNA, and in the regulation of intracellular thymidine levels. The enzyme exhibits broad substrate specificity, being able to process a wide range of pyrimidine nucleosides, including uridine, cytidine, and deoxyuridine. TP is a dimeric protein composed of two identical subunits, each containing a pyrimidine nucleoside-binding site and a phosphate-binding site. The active site of TP is located at the interface between the two subunits and is characterized by a highly conserved amino acid sequence. The mechanism of TP catalysis involves a two-step process. In the first step, the enzyme binds both the pyrimidine nucleoside and phosphate, forming a ternary complex. In the second step, the nucleoside is cleaved by the enzyme, releasing the free base and deoxyribose-1-phosphate. The reaction is reversible, allowing for the synthesis of thymidine from thymine and deoxyribose-1-phosphate. The activity of TP is regulated by a variety of factors, including pH, temperature, and the presence of inhibitors. TP is widely distributed in various tissues and organisms, including bacteria, yeast, plants, and animals. In humans, TP is expressed in a variety of tissues, including the liver, kidney, and small intestine. TP has been implicated in a number of biological processes, including cell proliferation, angiogenesis, and tumor growth. The enzyme has also been proposed as a target for the development of new anticancer drugs.'
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Proteins (3)

Compounds (27)