Guanylate kinase; Essential for recycling GMP and indirectly, cGMP.

Catalyzes the formation of inosine monophosphate from hypoxanthine and 5-phospho-alpha-D-ribose 1-diphosphate; Derived by automated computational analysis using gene prediction method: Protein Homology; Belongs to the purine/pyrimidine phosphoribosyltransferase family.

Guanosine kinase; Catalyzes the formation of inosine/guanosine monophosphate from inosine or guanosine and ATP; Derived by automated computational analysis using gene prediction method: Protein Homology.

Inosine-5-monophosphate dehydrogenase; Catalyzes the conversion of inosine 5'-phosphate (IMP) to xanthosine 5'-phosphate (XMP), the first committed and rate-limiting step in the de novo synthesis of guanine nucleotides, and therefore plays an important role in the regulation of cell growth. Belongs to the IMPDH/GMPR family.

Purine nucleoside phosphorylase; Catalyzes the reversible phosphorolysis of ribonucleosides and 2'- deoxyribonucleosides to the free base and (2'-deoxy)ribose-1- phosphate; Derived by automated computational analysis using gene prediction method: Protein Homology.

Guanosine 5'-monophosphate oxidoreductase; Catalyzes the irreversible NADPH-dependent deamination of GMP to IMP. It functions in the conversion of nucleobase, nucleoside and nucleotide derivatives of G to A nucleotides, and in maintaining the intracellular balance of A and G nucleotides.

Nucleoside-triphosphate diphosphatase; Pyrophosphatase that catalyzes the hydrolysis of nucleoside triphosphates to their monophosphate derivatives, with a high preference for the non-canonical purine nucleotides XTP (xanthosine triphosphate), dITP (deoxyinosine triphosphate) and ITP. Seems to function as a house-cleaning enzyme that removes non-canonical purine nucleotides from the nucleotide pool, thus preventing their incorporation into DNA/RNA and avoiding chromosomal lesions. Belongs to the HAM1 NTPase family.

Purine nucleoside phosphorylase; The purine nucleoside phosphorylases catalyze the phosphorolytic breakdown of the N-glycosidic bond in the beta- (deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate.

Stationary phase survival protein SurE; Nucleotidase with a broad substrate specificity as it can dephosphorylate various ribo- and deoxyribonucleoside 5'-monophosphates and ribonucleoside 3'-monophosphates with highest affinity to 3'-AMP. Also hydrolyzes polyphosphate (exopolyphosphatase activity) with the preference for short-chain-length substrates (P20-25). Might be involved in the regulation of dNTP and NTP pools, and in the turnover of 3'-mononucleotides produced by numerous intracellular RNases (T1, T2, and F) during the degradation of various RNAs.