Target type: molecularfunction
Catalysis of the reaction: diphosphate + nicotinate D-ribonucleotide = 5-phospho-alpha-D-ribose 1-diphosphate + H+ + nicotinate. [PMID:7503993]
Nicotinate phosphoribosyltransferase (NAPRT) is an enzyme that catalyzes the transfer of a phosphoribosyl group from 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) to nicotinate, forming nicotinate mononucleotide (NaMN). This reaction is a crucial step in the de novo biosynthesis of NAD+, a vital coenzyme involved in numerous metabolic processes.
The molecular function of NAPRT involves several key aspects:
1. **Substrate Binding:** NAPRT binds both nicotinate and PRPP at its active site. The enzyme exhibits high specificity for its substrates, ensuring efficient catalysis of the desired reaction.
2. **Phosphoribosyl Transfer:** NAPRT facilitates the transfer of the phosphoribosyl moiety from PRPP to the carboxyl group of nicotinate. This transfer is essential for the formation of NaMN, the precursor to NAD+.
3. **Catalysis:** The reaction catalyzed by NAPRT involves a series of steps:
- Binding of both substrates to the active site.
- Formation of a transient covalent intermediate between the enzyme and PRPP.
- Transfer of the phosphoribosyl group from the enzyme-PRPP intermediate to nicotinate.
- Release of NaMN from the active site.
4. **Regulation:** The activity of NAPRT is regulated by various factors, including:
- Feedback inhibition by NAD+, the final product of the pathway.
- Allosteric regulation by other metabolites, such as ATP and ADP.
5. **Cellular Localization:** NAPRT is primarily found in the cytoplasm of cells, reflecting its role in de novo NAD+ biosynthesis.
In summary, NAPRT plays a vital role in NAD+ biosynthesis by catalyzing the conversion of nicotinate to NaMN. The enzyme's molecular function involves substrate binding, phosphoribosyl transfer, catalysis, and regulation, all of which contribute to its essential role in maintaining cellular NAD+ levels.'
"
| Protein | Definition | Taxonomy |
|---|---|---|
| Nicotinate phosphoribosyltransferase | A nicotinate phosphoribosyltransferase that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q6XQN6] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 2-(3-pyridine)acetic acid | 3-pyridylacetic acid : A monocarboxylic acid that is acetic acid substituted by a (pyridin-3-yl) group. It is a metabolite of nicotine and other tobacco alkaloids. | monocarboxylic acid; pyridines | human xenobiotic metabolite |
| benzoic acid | aromatic carboxylic acid : Any carboxylic acid in which the carboxy group is directly bonded to an aromatic ring. benzoic acid : A compound comprising a benzene ring core carrying a carboxylic acid substituent. Benzoic Acid: A fungistatic compound that is widely used as a food preservative. It is conjugated to GLYCINE in the liver and excreted as hippuric acid. | benzoic acids | algal metabolite; antimicrobial food preservative; drug allergen; EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor; EC 3.1.1.3 (triacylglycerol lipase) inhibitor; human xenobiotic metabolite; plant metabolite |
| salicylic acid | Scalp: The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL). | monohydroxybenzoic acid | algal metabolite; antifungal agent; antiinfective agent; EC 1.11.1.11 (L-ascorbate peroxidase) inhibitor; keratolytic drug; plant hormone; plant metabolite |
| acetanilide | acetanilide: a phenylacetamide; use ACETANILIDES for the plural group meaning of the singular term N-phenylacetamide : A member of the class of acetamides that is acetamide in which one of the hydrogens attached to the nitrogen is substituted by a phenyl group. | acetamides; anilide | analgesic |
| picolinic acid | picolinic acid : A pyridinemonocarboxylic acid in which the carboxy group is located at position 2. It is an intermediate in the metabolism of tryptophan. picolinic acid: iron-chelating agent that inhibits DNA synthesis; may interfere with iron-dependent production of stable free organic radical which is essential for ribonucleotide reductase formation of deoxyribonucleotides; RN given refers to parent cpd; structure in Merck Index, 9th ed, #7206 | pyridinemonocarboxylic acid | human metabolite; MALDI matrix material |
| pyrazinoic acid | pyrazine-2-carboxylic acid : The parent compound of the class of pyrazinecarboxylic acids, that is pyrazine bearing a single carboxy substituent. The active metabolite of the antitubercular drug pyrazinamide. pyrazinoic acid: active metabolite of pyrazinamide; structure | pyrazinecarboxylic acid | antitubercular agent; drug metabolite |
| pyridine | azine : An organonitrogen compound of general structure RCH=N-N=CHR or RR'C=N-N=CRR'. | azaarene; mancude organic heteromonocyclic parent; monocyclic heteroarene; pyridines | environmental contaminant; NMR chemical shift reference compound |
| antipyrine | antipyrine : A pyrazolone derivative that is 1,2-dihydropyrazol-3-one substituted with methyl groups at N-1 and C-5 and with a phenyl group at N-2. Antipyrine: An analgesic and antipyretic that has been given by mouth and as ear drops. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. (From Martindale, The Extra Pharmacopoeia, 30th ed, p29) | pyrazolone | antipyretic; cyclooxygenase 3 inhibitor; environmental contaminant; non-narcotic analgesic; non-steroidal anti-inflammatory drug; xenobiotic |
| aspirin | acetylsalicylate : A benzoate that is the conjugate base of acetylsalicylic acid, arising from deprotonation of the carboxy group. acetylsalicylic acid : A member of the class of benzoic acids that is salicylic acid in which the hydrogen that is attached to the phenolic hydroxy group has been replaced by an acetoxy group. A non-steroidal anti-inflammatory drug with cyclooxygenase inhibitor activity. Aspirin: The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5) | benzoic acids; phenyl acetates; salicylates | anticoagulant; antipyretic; cyclooxygenase 1 inhibitor; cyclooxygenase 2 inhibitor; drug allergen; EC 1.1.1.188 (prostaglandin-F synthase) inhibitor; geroprotector; non-narcotic analgesic; non-steroidal anti-inflammatory drug; plant activator; platelet aggregation inhibitor; prostaglandin antagonist; teratogenic agent |
| flufenamic acid | flufenamic acid : An aromatic amino acid consisting of anthranilic acid carrying an N-(trifluoromethyl)phenyl substituent. An analgesic and anti-inflammatory, it is used in rheumatic disorders. Flufenamic Acid: An anthranilic acid derivative with analgesic, anti-inflammatory, and antipyretic properties. It is used in musculoskeletal and joint disorders and administered by mouth and topically. (From Martindale, The Extra Pharmacopoeia, 30th ed, p16) | aromatic amino acid; organofluorine compound | antipyretic; EC 1.14.99.1 (prostaglandin-endoperoxide synthase) inhibitor; non-narcotic analgesic; non-steroidal anti-inflammatory drug |
| indomethacin | indometacin : A member of the class of indole-3-acetic acids that is indole-3-acetic acid in which the indole ring is substituted at positions 1, 2 and 5 by p-chlorobenzoyl, methyl, and methoxy groups, respectively. A non-steroidal anti-inflammatory drug, it is used in the treatment of musculoskeletal and joint disorders including osteoarthritis, rheumatoid arthritis, gout, bursitis and tendinitis. Indomethacin: A non-steroidal anti-inflammatory agent (NSAID) that inhibits CYCLOOXYGENASE, which is necessary for the formation of PROSTAGLANDINS and other AUTACOIDS. It also inhibits the motility of POLYMORPHONUCLEAR LEUKOCYTES. | aromatic ether; indole-3-acetic acids; monochlorobenzenes; N-acylindole | analgesic; drug metabolite; EC 1.14.99.1 (prostaglandin-endoperoxide synthase) inhibitor; environmental contaminant; gout suppressant; non-steroidal anti-inflammatory drug; xenobiotic; xenobiotic metabolite |
| mefenamic acid | mefenamic acid : An aminobenzoic acid that is anthranilic acid in which one of the hydrogens attached to the nitrogen is replaced by a 2,3-dimethylphenyl group. Although classed as a non-steroidal anti-inflammatory drug, its anti-inflammatory properties are considered to be minor. It is used to relieve mild to moderate pain, including headaches, dental pain, osteoarthritis and rheumatoid arthritis. Mefenamic Acid: A non-steroidal anti-inflammatory agent with analgesic, anti-inflammatory, and antipyretic properties. It is an inhibitor of cyclooxygenase. | aminobenzoic acid; secondary amino compound | analgesic; antipyretic; antirheumatic drug; EC 1.14.99.1 (prostaglandin-endoperoxide synthase) inhibitor; environmental contaminant; non-steroidal anti-inflammatory drug; xenobiotic |
| oxyphenbutazone | oxyphenbutazone : A metabolite of phenylbutazone obtained by hydroxylation at position 4 of one of the phenyl rings. Commonly used (as its hydrate) to treat pain, swelling and stiffness associated with arthritis and gout, it was withdrawn from the market 1984 following association with blood dyscrasis and Stevens-Johnson syndrome. Oxyphenbutazone: A non-steroidal anti-inflammatory drug. Oxyphenbutazone eyedrops have been used abroad in the management of postoperative ocular inflammation, superficial eye injuries, and episcleritis. (From AMA, Drug Evaluations Annual, 1994, p2000) It had been used by mouth in rheumatic disorders such as ankylosing spondylitis, osteoarthritis, and rheumatoid arthritis but such use is no longer considered justified owing to the risk of severe hematological adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p27) | phenols; pyrazolidines | antimicrobial agent; antineoplastic agent; antipyretic; drug metabolite; gout suppressant; non-narcotic analgesic; non-steroidal anti-inflammatory drug; xenobiotic metabolite |
| phenylbutazone | phenylbutazone : A member of the class of pyrazolidines that is 1,2-diphenylpyrazolidine-3,5-dione carrying a butyl group at the 4-position. Phenylbutazone: A butyl-diphenyl-pyrazolidinedione that has anti-inflammatory, antipyretic, and analgesic activities. It has been used in ANKYLOSING SPONDYLITIS; RHEUMATOID ARTHRITIS; and REACTIVE ARTHRITIS. | pyrazolidines | antirheumatic drug; EC 1.1.1.184 [carbonyl reductase (NADPH)] inhibitor; metabolite; non-narcotic analgesic; non-steroidal anti-inflammatory drug; peripheral nervous system drug |
| sulfinpyrazone | Sulfinpyrazone: A uricosuric drug that is used to reduce the serum urate levels in gout therapy. It lacks anti-inflammatory, analgesic, and diuretic properties. | pyrazolidines; sulfoxide | uricosuric drug |
| isonicotinic acid | isonicotinic acid : A pyridinemonocarboxylic acid in which the carboxy group is at position 4 of the pyridine ring. | pyridinemonocarboxylic acid | algal metabolite; human metabolite |
| aminopyrine | aminophenazone : A pyrazolone that is 1,2-dihydro-3H-pyrazol-3-one substituted by a dimethylamino group at position 4, methyl groups at positions 1 and 5 and a phenyl group at position 2. It exhibits analgesic, anti-inflammatory, and antipyretic properties. Aminopyrine: A pyrazolone with analgesic, anti-inflammatory, and antipyretic properties but has risk of AGRANULOCYTOSIS. A breath test with 13C-labeled aminopyrine has been used as a non-invasive measure of CYTOCHROME P-450 metabolic activity in LIVER FUNCTION TESTS. | pyrazolone; tertiary amino compound | antipyretic; environmental contaminant; non-narcotic analgesic; non-steroidal anti-inflammatory drug; xenobiotic |
| 2-hydroxynicotinic acid | aromatic carboxylic acid; pyridines | ||
| 2-aminonicotinic acid | 2-aminonicotinic acid : An aminonicotinic acid in which the amino group is situated at position 2 of the pyridine ring. 2-aminonicotinic acid: structure in first source aminonicotinic acid : An aromatic amino acid that is nicotinic acid in which one of the hydrogens attached to the pyridine ring is replaced by an amino group. A 'closed class'. | aminonicotinic acid; aminopyridine | metabolite |
| 6-chloronicotinic acid | aromatic carboxylic acid; pyridines |