Page last updated: 2024-10-24

NAD metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving nicotinamide adenine dinucleotide (NAD), a coenzyme present in most living cells and derived from the B vitamin nicotinic acid. [GOC:jl, ISBN:0618254153]

NAD metabolic process encompasses a series of biochemical reactions that involve the synthesis, degradation, and utilization of nicotinamide adenine dinucleotide (NAD). NAD is a crucial coenzyme involved in numerous metabolic pathways, playing a vital role in energy production, redox reactions, and signaling cascades. The NAD metabolic process can be broadly categorized into two main stages: NAD biosynthesis and NAD degradation.

**NAD biosynthesis:**

* **De novo synthesis:** This pathway involves the conversion of tryptophan or nicotinic acid (niacin) into nicotinamide mononucleotide (NMN). NMN is then phosphorylated to NAD by the enzyme NMN adenylyltransferase.
* **Precursor salvage pathway:** This pathway utilizes pre-existing nicotinamide, nicotinic acid, or nicotinamide riboside to produce NAD. These precursors are salvaged and converted to NAD through specific enzymatic reactions.

**NAD degradation:**

* NAD is degraded into nicotinamide, which can be recycled back into the biosynthesis pathway.
* NAD can also be hydrolyzed to nicotinamide riboside and adenosine diphosphate ribose (ADPR). ADPR can be further metabolized into ADP-ribose, a signaling molecule involved in various cellular processes.

**Functions of NAD:**

* **Redox reactions:** NAD acts as an electron carrier in numerous redox reactions, including glycolysis, the citric acid cycle, and oxidative phosphorylation. It shuttles electrons between different metabolic pathways, facilitating energy production.
* **DNA repair:** NAD is a substrate for poly(ADP-ribose) polymerase (PARP), an enzyme involved in DNA damage repair. PARP utilizes NAD to generate poly(ADP-ribose) chains, which contribute to the repair process.
* **Signaling pathways:** NAD is involved in various signaling pathways, including the regulation of calcium homeostasis, apoptosis, and cell proliferation.

**Regulation of NAD metabolism:**

* NAD levels are tightly regulated by various factors, including nutritional intake, metabolic stress, and hormonal signals.
* Enzymes involved in NAD biosynthesis and degradation are subject to regulation by various mechanisms, ensuring optimal NAD levels for cellular function.

**Clinical implications:**

* NAD metabolism is linked to various diseases, including cancer, neurodegenerative disorders, and metabolic diseases.
* Therapeutic strategies targeting NAD metabolism are being investigated for the treatment of these diseases.

Overall, NAD metabolic process plays a critical role in maintaining cellular function and homeostasis. Its intricate regulation ensures the optimal availability of NAD for various metabolic pathways and signaling cascades, highlighting its importance in human health.'
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Proteins (5)

ProteinDefinitionTaxonomy
ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1An ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1 that is encoded in the genome of human. [PRO:WCB, UniProtKB:P28907]Homo sapiens (human)
ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1An ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1 that is encoded in the genome of human. [PRO:WCB, UniProtKB:P28907]Homo sapiens (human)
L-lactate dehydrogenase B chainAn L-lactate dehydrogenase B chain that is encoded in the genome of human. [PRO:DNx, UniProtKB:P07195]Homo sapiens (human)
NAD kinaseAn NAD kinase that is encoded in the genome of human. [PRO:DNx, UniProtKB:O95544]Homo sapiens (human)
Kynurenine 3-monooxygenaseA kynurenine 3-monooxygenase that is encoded in the genome of human. [PRO:DNx, UniProtKB:O15229]Homo sapiens (human)

Compounds (36)

CompoundDefinitionClassesRoles
taxifolin3'-hydroxyflavanones;
4'-hydroxyflavanones;
dihydroflavonols;
pentahydroxyflavanone;
secondary alpha-hydroxy ketone
oxamic acidoxamic acid : A dicarboxylic acid monoamide resulting from the formal condensation of one of the carboxy groups of oxalic acid with ammonia.

Oxamic Acid: Amino-substituted glyoxylic acid derivative.
dicarboxylic acid monoamideEscherichia coli metabolite
catechinhydroxyflavan
gossypolGossypol: A dimeric sesquiterpene found in cottonseed (GOSSYPIUM). The (-) isomer is active as a male contraceptive (CONTRACEPTIVE AGENTS, MALE) whereas toxic symptoms are associated with the (+) isomer.
guanidine hydrochlorideone-carbon compound;
organic chloride salt
protein denaturant
1-hydroxy-2-naphthoic acid1-hydroxy-2-naphthoic acid : A naphthoic acid with the carboxy group at position 2 and carrying a hydroxy substituent at the 1-position. It is a xenobiotic metabolite produced by the biodegradation of phenanthrene by microorganisms.

1-hydroxy-2-naphthoic acid: RN given refers to parent cpd
hydroxy monocarboxylic acid;
naphthoic acid;
naphthols
bacterial xenobiotic metabolite;
fungal xenobiotic metabolite
2,4-pyridinedicarboxylic acidlutidinic acid : A pyridinedicarboxylic acid carrying carboxy groups at positions 2 and 4.pyridinedicarboxylic acid
epigallocatechin gallate(-)-epigallocatechin 3-gallate : A gallate ester obtained by the formal condensation of gallic acid with the (3R)-hydroxy group of (-)-epigallocatechin.

epigallocatechin gallate: a steroid 5alpha-reductase inhibitor and antimutagen in green tea (Camellia sinensis)
flavans;
gallate ester;
polyphenol
antineoplastic agent;
antioxidant;
apoptosis inducer;
geroprotector;
Hsp90 inhibitor;
neuroprotective agent;
plant metabolite
gallocatechol(-)-epigallocatechin : A flavan-3,3',4',5,5',7-hexol having (2R,3R)-configuration.catechin;
flavan-3,3',4',5,5',7-hexol
antioxidant;
food component;
plant metabolite
gossylic nitrile-1,1'-diacetategossylic nitrile-1,1'-diacetate: inhibits human immunodeficiency virus Type I replication; structure given in first source
(3-nitrobenzoyl)alanine(3-nitrobenzoyl)alanine: inhibits kynurenine hydroxylase; structure in first source
delphinidindelphinidin : An anthocyanidin cation consisting of benzopyrylium with hydroxy substituents at the 3-, 5- and 7-positions and a 3,4,5-trihydroxyphenyl group at the 2-position. It is a plant pigment responsible for the colours of the plants of the genera Viola and Delphinium.

delphinidin: RN given refers to parent cpd;
5-hydroxyanthocyanidinantineoplastic agent;
biological pigment;
plant metabolite
cyanidincyanidin cation : An anthocyanidin cation that is flavylium substituted at positions 3, 3', 4', 5 and 7 by hydroxy groups.

cyanidin: RN given refers to parent cpd; structure
5-hydroxyanthocyanidinantioxidant;
metabolite;
neuroprotective agent
benzamide adenine nucleotidebenzamide adenine nucleotide: structure given in first source
tecadenosontecadenoson: an A1 adenosine receptor agonist
malvidinmalvidin : An anthocyanidin cation that is delphinidin carrying methyl substituents at positions 3' and 5'.

malvidin: RN given refers to parent cpd; coloring agent from flowers of Malvaviscus conzatti
5-hydroxyanthocyanidinbiological pigment;
metabolite
pelargonidinpelargonidin : An anthocyanidin cation that is flavylium substituted by a hydroxy groups at positions 3, 5, 7 and 4'.

pelargonidin: influences flower phenotype
5-hydroxyanthocyanidinplant metabolite
cyanidin 3-o-beta-d-glucopyranosidecyanidin 3-O-beta-D-glucoside : An anthocyanin cation that is a cyanidin cation linked to a beta-D-glucosyl moiety at position 3.anthocyanin cation;
beta-D-glucoside;
monosaccharide derivative
metabolite
buclizineluteolinidin: structure in first source5-hydroxyanthocyanidin
peonidinpeonidin : An anthocyanidin cation that is flavylium bearing four hydroxy substituents at positions 3, 4', 5 and 7 as well as a methoxy substituent at position 3'.

peonidin: a COX-2 inhibitor with protein kinase inhibitory and phytogenic antineoplastic activities; RN given for chloride salt
5-hydroxyanthocyanidinantineoplastic agent;
antioxidant;
apoptosis inducer;
metabolite
petunidinpetunidin : An anthocyanidin cation that is flavylium bearing five hydroxy substituents at positions 3, 3', 4', 5 and 7 as well as a methoxy substituent at position 5'.

petunidin: RN given for chloride salt
5-hydroxyanthocyanidinplant metabolite
resveratroltrans-resveratrol : A resveratrol in which the double bond has E configuration.resveratrolantioxidant;
phytoalexin;
plant metabolite;
quorum sensing inhibitor;
radical scavenger
3,3',4,5'-tetrahydroxystilbene3,3',4,5'-tetrahydroxystilbene: demethyl derivative of isorhapontigenin; structure in first source; a Syk kinase inhibitor; found in heartwood of FABACEAE; inhibitor of photosynthesis in spinach chloroplasts; may be inhibitor of plant growth; RN given refers to (E)-isomer

piceatannol : A stilbenol that is trans-stilbene in which one of the phenyl groups is substituted by hydroxy groups at positions 3 and 4, while the other phenyl group is substituted by hydroxy groups at positions 3 and 5.
catechols;
polyphenol;
resorcinols;
stilbenol
antineoplastic agent;
apoptosis inducer;
geroprotector;
hypoglycemic agent;
plant metabolite;
protein kinase inhibitor;
tyrosine kinase inhibitor
oxalylglycineN-oxalylglycine : An amino dicarboxylic acid that is iminodiacetic acid with an oxo substituent. It is used as an inhibitor of alpha-ketoglutarate dependent (EC 1.14.11.*) enzymes.

oxalylglycine: structure given in first source
amino dicarboxylic acid;
N-acylglycine
EC 1.14.11.* (oxidoreductase acting on paired donors, 2-oxoglutarate as one donor, incorporating 1 atom each of oxygen into both donors) inhibitor
ex 5276-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide : A member of the class of carbazoles that is 2,3,4,9-tetrahydro-1H-carbazole which is substituted at position 1 by an aminocarbohyl group and at position 6 by a chlorine.

6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide: structure in first source
carbazoles;
monocarboxylic acid amide;
organochlorine compound
quercetin7-hydroxyflavonol;
pentahydroxyflavone
antibacterial agent;
antineoplastic agent;
antioxidant;
Aurora kinase inhibitor;
chelator;
EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor;
geroprotector;
phytoestrogen;
plant metabolite;
protein kinase inhibitor;
radical scavenger
luteolin3'-hydroxyflavonoid;
tetrahydroxyflavone
angiogenesis inhibitor;
anti-inflammatory agent;
antineoplastic agent;
apoptosis inducer;
c-Jun N-terminal kinase inhibitor;
EC 2.3.1.85 (fatty acid synthase) inhibitor;
immunomodulator;
nephroprotective agent;
plant metabolite;
radical scavenger;
vascular endothelial growth factor receptor antagonist
myricetin7-hydroxyflavonol;
hexahydroxyflavone
antineoplastic agent;
antioxidant;
cyclooxygenase 1 inhibitor;
food component;
geroprotector;
hypoglycemic agent;
plant metabolite
quercetagetinquercetagetin : A hexahydroxyflavone that is flavone substituted by hydroxy groups at positions 3, 5, 6, 7, 3' and 4' respectively.

quercetagetin: structure given in first source; inhibits aldose reductase in rat lens
flavonols;
hexahydroxyflavone
antioxidant;
antiviral agent;
plant metabolite
robinetinrobinetin : A pentahydroxyflavone that is flavone substituted by hydroxy groups at positions 3, 7, 3, 4' and 5'.

robinetin: structure given in first source
7-hydroxyflavonol;
pentahydroxyflavone
plant metabolite
ro 61-8048C-nitro compound
3-dihydroxy-6-methyl-7-(phenylmethyl)-4-propylnaphthalene-1-carboxylic acid3-dihydroxy-6-methyl-7-(phenylmethyl)-4-propylnaphthalene-1-carboxylic acid: inhibits lactate dehydrogenase A
adenosine monophosphateadenosine 5'-monophosphate(2-) : A nucleoside 5'-monophosphate(2-) that results from the removal of two protons from the phosphate group of adenosine 5'-monophosphate (AMP).nucleoside 5'-monophosphate(2-)cofactor;
fundamental metabolite;
human metabolite
galloflavingalloflavin: structure in first source
gossylic iminolactonegossylic iminolactone: inhibits human immunodeficiency virus type I replication; structure given in first source
gossylic lactonegossylic lactone: inhibits human immunodeficiency virus type I replication; structure given in first source