Nucleotide kinase and related adenine nucleotide-binding enzyme

Nucleotide kinases and related adenine nucleotide-binding enzymes are a broad class of enzymes, primarily transferases, that play a fundamental role in cellular metabolism by regulating the phosphorylation state of nucleotides (Mulligan, 2021, PubMed). These enzymes, which often contain a conserved P-loop (Walker A) motif for ATP binding, are essential for the synthesis of DNA and RNA precursors and the maintenance of energy homeostasis via the interconversion of adenine nucleotides like ATP, ADP, and AMP (Yan and Tsai, 1999, PubMed). In clinical practice, this group is highly significant because many antiviral and anticancer nucleoside analogs, such as zidovudine and gemcitabine, function as prodrugs that must be sequentially phosphorylated by host or viral nucleotide kinases to reach their active triphosphate forms (Galmarini et al., 2002, The Lancet Oncology). Furthermore, specific members like thymidine kinase 1 (TK1) serve as important serum biomarkers for cellular proliferation and tumor aggressiveness (Topolcan and Holubec, 2008, Expert Opinion on Medical Diagnostics). Therapeutic challenges associated with targeting these enzymes include potential mitochondrial toxicity and bone marrow suppression, often resulting from the inhibition of mitochondrial DNA polymerase or the disruption of endogenous nucleotide pools (Lewis and Dalakas, 1995, Nature Medicine). The high degree of structural conservation in the ATP-binding sites across different kinases also poses a significant hurdle for developing highly selective inhibitors without off-target effects. Overall, these enzymes are central to both basic cellular viability and the efficacy of a wide range of modern pharmacotherapies.

Other names

Nucleoside phosphate kinaseP-loop kinaseATP-binding enzymeNucleoside monophosphate kinaseNucleoside diphosphate kinase

Activation of nucleoside analog prodrugs via sequential phosphorylation to active triphosphate forms; competitive inhibition of natural nucleotide substrates (Galmarini et al., 2002, The Lancet Oncology).