| Role | Gene | Name | |
|---|
| 3-hydroxyanthranilate 3,4-dioxygenase (EC 1.13.11.6) | No genes | | |
| ADP-ribose pyrophosphatase (EC 3.6.1.13) | b3034 | nudF | |
| Amidases related to nicotinamidase | No genes | | |
| C-terminal domain of CinA type S | No genes | | |
| C-terminal domain of CinA type S homolog | No genes | | |
| Glutamine amidotransferase chain of NAD synthetase | No genes | | |
| Indoleamine 2,3-dioxygenase (EC 1.13.11.52) | No genes | | |
| Isochorismatase (EC 3.3.2.1) of siderophore biosynthesis | No genes | | |
| Kynureninase (EC 3.7.1.3) | No genes | | |
| Kynurenine 3-monooxygenase (EC 1.14.13.9) | No genes | | |
| Kynurenine formamidase (EC 3.5.1.9) | No genes | | |
| Kynurenine formamidase, bacterial (EC 3.5.1.9) | No genes | | |
| Kynurenine formamidase, yeast-type BNA7 (EC 3.5.1.9) | No genes | | |
| L-Aspartate dehydrogenase (EC 1.4.1.21) | No genes | | |
| L-aspartate oxidase (EC 1.4.3.16) | b2574 | nadB | |
| N-Ribosylnicotinamide phosphorylase (EC 2.4.2.1) | No genes | | |
| NAD kinase (EC 2.7.1.23) | b2615 | yfjB | |
| NAD pyrophosphatase, periplasmic (EC 3.6.1.22) | No genes | | |
| NAD synthetase (EC 6.3.1.5) | b1740 | nadE | |
| NAD transporter of endosymbionts, possible | No genes | | |
| NMN 5'-nucleotidase, extracellular (EC 3.1.3.5) | No genes | | |
| NMN phosphatase (EC 3.1.3.5) | No genes | | |
| NMN synthetase (EC 6.3.1.-) | No genes | | |
| NadR transcriptional regulator | b4390 | nadR | |
| Niacin transporter NiaP | No genes | | |
| Niacin transporter in yeast, DAL5 family | No genes | | |
| Nicotinamidase (EC 3.5.1.19) | b1768 | ydjB | |
| Nicotinamidase family protein YcaC | b0897 | ycaC | |
| Nicotinamidase/isochorismatase family protein | b1867 | yecD | |
| Nicotinamide phosphoribosyltransferase (EC 2.4.2.12) | No genes | | |
| Nicotinamide-nucleotide adenylyltransferase (EC 2.7.7.1) | No genes | | |
| Nicotinamide-nucleotide adenylyltransferase (EC 2.7.7.1), eukaryotic PNAT family | No genes | | |
| Nicotinamide-nucleotide adenylyltransferase, NadM family (EC 2.7.7.1) | No genes | | |
| Nicotinamide-nucleotide adenylyltransferase, NadR family (EC 2.7.7.1) | b4390 | nadR | |
| Nicotinate phosphoribosyltransferase (EC 2.4.2.11) | b0931 | pncB | |
| Nicotinate-nucleotide adenylyltransferase (EC 2.7.7.18) | b0639 | nadD | |
| Nicotinate-nucleotide adenylyltransferase (EC 2.7.7.18), eukaryotic PNAT family | No genes | | |
| Nicotinate-nucleotide adenylyltransferase, NadM family (EC 2.7.7.18) | No genes | | |
| Nicotine adenine dinucleotide glycohydrolase (NADGH) (EC 3.2.2.5) | No genes | | |
| Nudix-related transcriptional regulator NrtR | No genes | | |
| Predicted N-ribosylNicotinamide CRP-like regulator | b2163 | yeiL | |
| Quinolinate phosphoribosyltransferase [decarboxylating] (EC 2.4.2.19) | b0109 | nadC | |
| Quinolinate synthetase (EC 2.5.1.72) | b0750 | nadA | |
| Ribosyl nicotinamide transporter, PnuC-like | b0751 | pnuC | |
| Ribosylnicotinamide kinase (EC 2.7.1.22) | b4390 | nadR | |
| Ribosylnicotinamide kinase, eukaryotic (EC 2.7.1.22) | No genes | | |
| Substrate-specific component NiaX of predicted niacin ECF transporter | No genes | | |
| Transcriptional repressor for NAD biosynthesis in gram-positives | No genes | | |
| Tryptophan 2,3-dioxygenase (EC 1.13.11.11) | No genes | | |