PnuC is the membrane protein responsible for nicotinamide mononucleotide transport; Contains seven transmembrane helices; Localized in the cytoplasmic membrane; High confidence in function and specificity.

TonB-dependent Receptor; Protein localized in the outer membrane involved in uptake of macromolecules that are too large to diffuse via the outer membrane porins channels or are encountered at very low concentrations; Does not contain of carboxypeptidase regulatory domain. The Plug module (41-152) acts as a channel gate; The signal peptide is cleaved between the residues 20 and 21; Family membership.

NH(3)-dependent NAD(+) synthetase; Catalyzes the ATP-dependent amidation of deamido-NAD to form NAD. Uses ammonia as a nitrogen source.

Conserved protein belonging to the CinA family. Contains a N-terminal molybdopterin binding domain and a C-terminal Competence-damaged domain. CinA is the first gene in the competence-inducible (cin) operon, and is thought to be specifically required at some stage in the process of transformation. Localized in the cytoplasm; Function unclear.

NAD(+) kinase; Involved in the regulation of the intracellular balance of NAD and NADP, and is a key enzyme in the biosynthesis of NADP. Catalyzes specifically the phosphorylation on 2'-hydroxyl of the adenosine moiety of NAD to yield NADP.

Quinolinic acid phosphoribosyl transferase (QPRTase or QAPRTase) or nicotinate-nucleotide pyrophosphorylase catalyses the conversion of quinolinic acid (QA) with 5-phosphoribosyl-1-pyrophosphate (PRPP), in the presence of Mg2+, to nicotinic acid mononucleotide (NAMN), pyrophosphate and carbon dioxide. This enzyme provides the de novo source of NAMN for NAD biosynthesis; Localized in the cytoplasm; High confidence in function and specificity; Belongs to the NadC/ModD family.

Nicotinate-nucleotide adenylyltransferase; Catalyzes the reversible adenylation of nicotinate mononucleotide (NaMN) to nicotinic acid adenine dinucleotide (NaAD).

5'-Nucleotidase, phosphatase subunit; The 5'-Nucleotidase is involved in the degradation of extracellular 5'-nucleotides into membrane permeable nucleosides. Usually It is composed of a N-terminal phosphatase domain that provides the ligands to the dimetal cluster and a conserved histidine, which together form the catalytic site and of a C-terminal domain involved in the substrate binding; This lipoprotein corresponds only to the phosphatase domain that hydrolyses the phosphate esterified at carbon 5' of the ribose and deoxyribose portions of nucleotide molecules; Binds a chloride ion [...]

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.