enzyme involved in redox reactions
In biochemistry , an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant , also called the electron donor , to another, the oxidant , also called the electron acceptor . This group of enzymes usually utilizes NADP+ or NAD+ as cofactors .[1] [2] Transmembrane oxidoreductases create electron transport chains in bacteria, chloroplasts and mitochondria , including respiratory complexes I , II and III . Some others can associate with biological membranes as peripheral membrane proteins or be anchored to the membranes through a single transmembrane helix .[3]
Reactions [ edit ] For example, an enzyme that catalyzed this reaction would be an oxidoreductase:
A– + B → A + B– In this example, A is the reductant (electron donor) and B is the oxidant (electron acceptor).
In biochemical reactions, the redox reactions are sometimes more difficult to see, such as this reaction from glycolysis :
Pi + glyceraldehyde-3-phosphate + NAD+ → NADH + H+ + 1,3-bisphosphoglycerate In this reaction, NAD+ is the oxidant (electron acceptor), and glyceraldehyde-3-phosphate is the reductant (electron donor).
Nomenclature [ edit ] Proper names of oxidoreductases are formed as "donor:acceptor oxidoreductase"; however, other names are much more common. The common name is "donor dehydrogenase " when possible, such as glyceraldehyde-3-phosphate dehydrogenase for the second reaction above. Common names are also sometimes formed as "acceptor reductase", such as NAD+ reductase. "Donor oxidase " is a special case where O 2 is the acceptor.
Classification [ edit ] Oxidoreductases are classified as EC 1 in the EC number classification of enzymes. Oxidoreductases can be further classified into 21 subclasses:
EC 1.1 includes oxidoreductases that act on the CH-OH group of donors (alcohol oxidoreductases )EC 1.2 includes oxidoreductases that act on the aldehyde or oxo group of donorsEC 1.3 includes oxidoreductases that act on the CH-CH group of donors (CH-CH oxidoreductases )EC 1.4 includes oxidoreductases that act on the CH-NH2 group of donors (Amino acid oxidoreductases , Monoamine oxidase )EC 1.5 includes oxidoreductases that act on CH-NH group of donorsEC 1.6 includes oxidoreductases that act on NADH or NADPH EC 1.7 includes oxidoreductases that act on other nitrogenous compounds as donors EC 1.8 includes oxidoreductases that act on a sulfur group of donors EC 1.9 includes oxidoreductases that act on a heme group of donors EC 1.10 includes oxidoreductases that act on diphenols and related substances as donors EC 1.11 includes oxidoreductases that act on peroxide as an acceptor (peroxidases) EC 1.12 includes oxidoreductases that act on hydrogen as donors EC 1.13 includes oxidoreductases that act on single donors with incorporation of molecular oxygen (oxygenases) EC 1.14 includes oxidoreductases that act on paired donors with incorporation of molecular oxygen EC 1.15 includes oxidoreductases that act on superoxide radicals as acceptors EC 1.16 includes oxidoreductases that oxidize metal ions EC 1.17 includes oxidoreductases that act on CH or CH2 groups EC 1.18 includes oxidoreductases that act on iron-sulfur proteins as donors EC 1.19 includes oxidoreductases that act on reduced flavodoxin as a donor EC 1.20 includes oxidoreductases that act on phosphorus or arsenic in donors EC 1.21 includes oxidoreductases that act on X-H and Y-H to form an X-Y bond See also [ edit] Hydroxylase List of enzymes References [ edit] ^ Eric J. Toone (2006). Advances in Enzymology and Related Areas of Molecular Biology, Protein Evolution (Volume 75 ed.). Wiley-Interscience. ISBN 0471205036. ^ Nicholas C. Price; Lewis Stevens (1999). Fundamentals of Enzymology: The Cell and Molecular Biology of Catalytic Proteins (Third ed.). USA: Oxford University Press. ISBN 019850229X. ^ Superfamilies of single-pass transmembrane oxidoreductases in Membranome database External links [ edit] Media related to Oxidoreductases at Wikimedia Commons EC 1 Introduction from the Department of Chemistry at Queen Mary, University of London 3-hydroxyacyl-CoA dehydrogenase 3-hydroxybutyryl-CoA dehydrogenase Alcohol dehydrogenase Aldo-keto reductase Aldose reductase Beta-Ketoacyl ACP reductase Carbohydrate dehydrogenases Carnitine dehydrogenase D-malate dehydrogenase (decarboxylating) DXP reductoisomerase Glucose-6-phosphate dehydrogenase Glycerol-3-phosphate dehydrogenase HMG-CoA reductase IMP dehydrogenase Isocitrate dehydrogenase Lactate dehydrogenase L-threonine dehydrogenase L-xylulose reductase Malate dehydrogenase Malate dehydrogenase (decarboxylating) Malate dehydrogenase (NADP+) Malate dehydrogenase (oxaloacetate-decarboxylating) Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) Phosphogluconate dehydrogenase Sorbitol dehydrogenase Hydroxysteroid dehydrogenase: 3β11β 17β D-lactate dehydrogenase (cytochrome) D-lactate dehydrogenase (cytochrome c-553) Mannitol dehydrogenase (cytochrome) Glucose oxidase L-gulonolactone oxidase Xanthine oxidase Alcohol oxidase Vitamin K epoxide reductase Vitamin-K-epoxide reductase (warfarin-insensitive) Malate dehydrogenase (quinone) Quinoprotein glucose dehydrogenase Choline dehydrogenase L2HGDH
Aldehyde dehydrogenaseAcetaldehyde dehydrogenase Long-chain-aldehyde dehydrogenase Formate dehydrogenase (cytochrome) Oxoglutarate dehydrogenase complex Pyruvate dehydrogenase Branched-chain alpha-keto acid dehydrogenase complex
Enoyl-acyl carrier protein reductase/Enoyl ACP reductase 7-Dehydrocholesterol reductase Biliverdin reductase 2,4 Dienoyl-CoA reductase Dihydroxymethyloxo-tetrahydroquinoline dehydrogenase Dihydroorotate dehydrogenase Coproporphyrinogen III oxidase Protoporphyrinogen oxidase Bilirubin oxidase Acyl-CoA oxidase Dihydrouracil oxidase Tetrahydroberberine oxidase Secologanin synthase Tryptophan alpha,beta-oxidase Pyrroloquinoline-quinone synthase L-galactonolactone oxidase Fumarate reductase Butyryl-CoA dehydrogenase Acyl CoA dehydrogenase 5α-reductase Glutaryl-CoA dehydrogenase Isovaleryl coenzyme A dehydrogenase 3-oxo-5beta-steroid 4-dehydrogenase
Glutamate dehydrogenase Glutamate synthase (NADPH) D-amino acid oxidase Amine oxidase (Copper-containing (Lysyl Diamine Primary-amine)) (Flavin-containing (Monoamine))) D-amino acid dehydrogenase Amine dehydrogenase
Dihydrofolate reductase Saccharopine dehydrogenase Methylenetetrahydrofolate reductase Dihydrobenzophenanthridine oxidase Sarcosine oxidase Proline oxidase Electron-transferring-flavoprotein dehydrogenase Sarcosine dehydrogenase Cytokinin dehydrogenase
NAD(P)+ transhydrogenase (Si-specific) NAD(P)+ transhydrogenase (Re/Si-specific) Methemoglobin reductase NADPH—hemoprotein reductase/Cytochrome P450 reductase NADPH—cytochrome-c2 reductase Leghemoglobin reductase NADPH oxidaseP91-PHOX Neutrophil cytosolic factor 1 Neutrophil cytosolic factor 2 Neutrophil cytosolic factor 4 dual oxidase Dual oxidase 1 Dual oxidase 2 Trimethylamine-N-oxide reductase NADH dehydrogenase (quinone)
Nitrite reductase (NO-forming) Ferredoxin—nitrite reductase
Dihydrolipoamide dehydrogenase Glutathione reductase Thioredoxin reductase Sulfite dehydrogenase Thiosulfate dehydrogenase Flavocytochrome c sulfide dehydrogenase Glutathione—homocystine transhydrogenase Glutathione dehydrogenase (ascorbate) CoB—CoM heterodisulfide reductase
Nitrate reductase (cytochrome) Iron—cytochrome-c reductase
Trans-acenaphthene-1,2-diol dehydrogenase Coenzyme Q - cytochrome c reductase
NADH peroxidase NADPH peroxidase Fatty-acid peroxidase Catalase Cytochrome c peroxidase Eosinophil peroxidase Glutathione peroxidase Horseradish peroxidase Lactoperoxidase Myeloperoxidase Thyroid peroxidase DeiodinaseIodothyronine deiodinase Iodotyrosine deiodinase
Hydrogen dehydrogenase Hydrogen dehydrogenase (NADP+) Hydrogenase (NAD+, ferredoxin) Cytochrome-c3 hydrogenase Hydrogen:quinone oxidoreductase Coenzyme F420 hydrogenase 5,10-Methenyltetrahydromethanopterin hydrogenase Methanosarcina-phenazine hydrogenase Sulfhydrogenase
lipoxygenase: Arachidonate 5-lipoxygenaseArachidonate 12-lipoxygenase/ALOX12 Arachidonate 8-lipoxygenase Arachidonate 15-lipoxygenase/ALOX15 Linoleate 11-lipoxygenase other dioxygenase: Catechol dioxygenaseHomogentisate 1,2-dioxygenase Cysteine dioxygenase 4-Hydroxyphenylpyruvate dioxygenase Indoleamine 2,3-dioxygenase Chlorite dismutase
Prolyl hydroxylaseHIF prolyl-hydroxylase P4HTM Lysyl hydroxylase Flavin-containing monooxygenase Nitric oxide synthase Cholesterol 7 alpha-hydroxylase Methane monooxygenase 3A4 14α-demethylase 24-hydroxycholesterol 7α-hydroxylase Phenylalanine hydroxylase Tyrosine hydroxylase Tryptophan hydroxylase Dopamine beta-hydroxylase Tyrosinase Stearoyl-CoA desaturase-1 Cyclooxygenase Heme oxygenase (HMOX1) Squalene monooxygenase 17A1 21A2 Ecdysone 20-monooxygenase
Ceruloplasmin (Methionine synthase) reductase Xanthine oxidase Ribonucleotide reductase 4-Hydroxy-3-methylbut-2-enyl diphosphate reductase Isopenicillin N synthase Columbamine oxidase Reticuline oxidase Sulochrin oxidase(+)-bisdechlorogeodin-forming (-)-bisdechlorogeodin-forming Aureusidin synthase Tetrahydrocannabinolic acid synthase Cannabidiolic acid synthase Dichlorochromopyrrolate synthase
Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator EC number Enzyme superfamily Enzyme family List of enzymes Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics EC1 Oxidoreductases (list)EC2 Transferases (list)EC3 Hydrolases (list)EC4 Lyases (list)EC5 Isomerases (list)EC6 Ligases (list)EC7 Translocases (list)