Substrate Specificity of a Thymidine Phosphorylase in Human Liver Tumor

• Published in: Chemical & pharmaceutical bulletin Vol. 32; no. 5; pp. 1919 - 1921
• Main Authors: KONO, AKIRA, HARA, YASUHIRO, SUGATA, SETSURO, MATSUSHIMA, YOSHIKAZU, UEDA, TOHRU
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 01.01.1984; Maruzen; Japan Science and Technology Agency
• Subjects: 5'-deoxy-5-fluorouridine; Adenocarcinoma - enzymology; Adenocarcinoma - secondary; Antineoplastic agents; Biological and medical sciences; Female; Gallbladder Neoplasms; General aspects; Humans; In Vitro Techniques; liver; Liver Neoplasms - enzymology; Liver Neoplasms - secondary; man; Medical sciences; Middle Aged; Pentosyltransferases - metabolism; Pharmacology. Drug treatments; Substrate Specificity; thymidine phosphorylase; Thymidine Phosphorylase - metabolism; tumors; Antineoplastic agent; Antimetabolic; Enzyme; Substrate specificity; Tumoral tissue; Activity metabolism relation
• ISSN: 0009-2363; 1347-5223
• DOI: 10.1248/cpb.32.1919

A thymidine phosphorylase preparation was partially purified from human liver tumor tissues (poorly differentiated adenocarcinoma). The substrate specificity of the enzyme was investigated with eleven pyrimidine nucleosides. Thymidine and 2'-deoxyuridine were good substrates, while uridine, 3'-deoxyuridine, 5'-deoxyuridine, and 2', 3'-dideoxy-3'-hydroxy-methyluridine were not. Uridines substituted at the 5-position by a cyano, bromo, or chloro group were also phosphorolyzed by the enzyme, but the activity for 5-fluorouridine was much lower. 5'-Deoxy-5-fluorouridine was also cleaved. Either a 5-substituent or a 2'-deoxy structure seems to be essential for a good substrate.