DNPH1 (also known as Rcl) is an enzyme involved in nucleotide metabolism. It catalyses the cleavage of the N-glycosidic bond of deoxyribonucleoside 5'-monophosphates to yield deoxyribose 5-phosphate and a purine or pyrimidine base []. Deoxyribonucleoside 5'-monophosphates containing purine bases are preferred to those containing pyrimidine bases. This enzyme is over-expressed in several cancers [], which may be a potential molecular target for cancer treatment [].
Nucleoside 2-deoxyribosyltransferase (NDT) () catalyses the cleavage of the glycosidic bonds of 2-deoxyribonucleosides. Nucleoside 2-deoxyribosyltransferases can be divided into two groups based on their substrate specificity: class I enzymes are specific for the transfer of deoxyribose between two purines, while class II enzymes will transfer the deoxyribose between either purines or pyrimidines. The structure of the class I []and class II []enzymes are very similar. In class I enzymes, the purine base shields the active site from solvent, which the smaller pyrimidine base cannot do, while in class II enzymes the active site is shielded by a loop (residues 48-62). Both classes of enzymes are found in various Lactobacillus species and participate in nucleoside recycling in these microorganisms. This entry represents both classes of enzymes.This entry also includes the related enzyme deoxynucleoside 5-monophosphate N-glycosidase (DNPH1), a nucleotide hydrolase (). DNPH1 is related to NDT in structure and enzymatic activity, but in contrast to NDT catalyzes the hydrolysis of 2'-deoxyribonucleoside 5'-monophosphate to yield a free nucleobase and 2-deoxyribose 5-phosphate [, ]. DNPH1 is a potential proto-oncogene [].
