Glycosyl transferase, family 3 <p>The glycosyl transferase family includes anthranilate phosphoribosyltransferase (TrpD, <db_xref db="EC" dbkey="2.4.2.18"/>) and thymidine phosphorylase (<db_xref db="EC" dbkey="2.4.2.2"/>). All these proteins can transfer a phosphorylated ribose substrate. Thymidine phosphorylase (<db_xref db="EC" dbkey="2.4.2.2"/>) catalyses the reversible phosphorolysis of thymidine, deoxyuridine and their analogues to their respective bases and 2-deoxyribose 1-phosphate. This enzyme regulates the availability of thymidine and is therefore essential to nucleic acid metabolism.</p>