Target type: molecularfunction
Catalysis of the reaction: NADPH + H+ + a quinone = NADP+ + a quinol. [RHEA:46164]
NADPH dehydrogenase (quinone) activity is a critical enzyme activity involved in the transfer of electrons from NADPH to quinone substrates. This activity is catalyzed by a family of enzymes known as NADPH dehydrogenases, which play crucial roles in various cellular processes, including: \\n\\n1. **Redox Homeostasis:** NADPH dehydrogenases contribute to maintaining cellular redox balance by reducing quinones, which are oxidized forms of quinols. This reduction process helps to regenerate the reduced form of quinols, which are essential for a variety of cellular processes, such as antioxidant defense and electron transport.\\n\\n2. **Reactive Oxygen Species (ROS) Detoxification:** Quinones can act as substrates for NADPH dehydrogenases, leading to the detoxification of ROS. By reducing quinones, these enzymes prevent the accumulation of harmful ROS, which can damage cellular components and contribute to oxidative stress.\\n\\n3. **Electron Transport Chain:** In some organisms, NADPH dehydrogenases are involved in the electron transport chain, where they transfer electrons from NADPH to specific quinones, contributing to energy production. This activity is particularly important in mitochondrial respiration and photosynthesis.\\n\\n4. **Drug Metabolism:** NADPH dehydrogenases can also play a role in drug metabolism by catalyzing the reduction of quinones present in certain drugs. This activity can affect the efficacy and toxicity of drugs.\\n\\n5. **Biosynthesis:** Some NADPH dehydrogenases participate in the biosynthesis of various cellular components, such as hormones and pigments, by reducing specific quinone substrates involved in these pathways.\\n\\nThe molecular mechanism of NADPH dehydrogenase (quinone) activity involves the following steps:\\n\\n1. **Binding of NADPH:** The enzyme binds to NADPH, which acts as the electron donor.\\n\\n2. **Binding of Quinone:** The quinone substrate binds to the enzyme's active site.\\n\\n3. **Electron Transfer:** An electron is transferred from NADPH to the quinone substrate, reducing the quinone to a quinol.\\n\\n4. **Product Release:** The reduced quinol is released from the enzyme, while the oxidized form of NADPH (NADP+) remains bound.\\n\\n5. **NADP+ Release:** NADP+ is released from the enzyme, allowing the cycle to repeat.\\n\\nIn summary, NADPH dehydrogenase (quinone) activity is a crucial enzyme activity that contributes to redox homeostasis, ROS detoxification, electron transport, drug metabolism, and biosynthesis. It involves the transfer of electrons from NADPH to quinone substrates, leading to the reduction of quinones and the generation of reduced quinols, which are essential for various cellular processes.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| NAD | An NAD(P)H dehydrogenase [quinone] 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P15559] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 4'-bromoflavone | 4'-bromoflavone: structure in first source | ||
| beta-naphthoflavone | beta-naphthoflavone : An extended flavonoid resulting from the formal fusion of a benzene ring with the f side of flavone. beta-Naphthoflavone: A polyaromatic hydrocarbon inducer of P4501A1 and P4501A2 cytochromes. (Proc Soc Exp Biol Med 1994 Dec:207(3):302-308) | extended flavonoid; naphtho-gamma-pyrone; organic heterotricyclic compound | aryl hydrocarbon receptor agonist |
| beta-lapachone | beta-lapachone : A benzochromenone that is 3,4-dihydro-2H-benzo[h]chromene-5,6-dione substituted by geminal methyl groups at position 2. Isolated from Tabebuia avellanedae, it exhibits antineoplastic and anti-inflammatory activities. beta-lapachone: antineoplastic inhibitor of reverse transcriptase, DNA topoisomerase, and DNA polymerase | benzochromenone; orthoquinones | anti-inflammatory agent; antineoplastic agent; plant metabolite |
| vitamin k 3 | Vitamin K 3: A synthetic naphthoquinone without the isoprenoid side chain and biological activity, but can be converted to active vitamin K2, menaquinone, after alkylation in vivo. | 1,4-naphthoquinones; vitamin K | angiogenesis inhibitor; antineoplastic agent; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; human urinary metabolite; nutraceutical |
| sulforaphane | sulforaphane : An isothiocyanate having a 4-(methylsulfinyl)butyl group attached to the nitrogen. sulforaphane: from Cardaria draba L. | isothiocyanate; sulfoxide | antineoplastic agent; antioxidant; EC 3.5.1.98 (histone deacetylase) inhibitor; plant metabolite |
| c 1303 | C 1303: DNa-binding drug; structure given indicates that the cpd should be the dimethylamino cpd, but it is named as the diethylamino cpd | ||
| nsc 366140 | NSC 366140: a 9-methoxypyrazoloacridine; structure given in first source | ||
| 5-methoxy-1,2-dimethyl-3-((4-nitrophenoxy)methyl)indole-4,7-dione | 5-methoxy-1,2-dimethyl-3-((4-nitrophenoxy)methyl)indole-4,7-dione: structure in first source | ||
| bisantrene | |||
| 4,3',5'-tri-o-methylpiceatannol | |||
| memoquin | memoquin: structure in first source | ||
| dicumarol | Dicumarol: An oral anticoagulant that interferes with the metabolism of vitamin K. It is also used in biochemical experiments as an inhibitor of reductases. | hydroxycoumarin | anticoagulant; EC 1.6.5.2 [NAD(P)H dehydrogenase (quinone)] inhibitor; Hsp90 inhibitor; vitamin K antagonist |
| ethyl biscoumacetate | Ethyl Biscoumacetate: A coumarin that is used as an anticoagulant. It has actions similar to those of WARFARIN. (From Martindale, The Extra Pharmacopoeia, 30th ed, p226) | hydroxycoumarin | |
| nsc 158393 | NSC 158393: structure given in first source |