Oxidoreductase enzymes catalyze the transfer of electrons from the reductant to the oxidant. These enzymes utilize NADP+ or NAD+ as cofactors.
Transmembrane oxidoreductase enzymes are found in electron transport chains of bacteria, chloroplast, and mitochondria. Some of these enzymes are also anchored to the peripheral membrane with the help of a transmembrane helix. A considerable number of oxidoreductase enzymes are widely studied in biochemistry.
Oxidoreductase enzyme examples:
- Aromatase
- Choline oxidase
- Laccase
- Dihydrofolate reductase
- Glutathione reductase
- Glyceraldehyde-3-Phosphate Dehydrogenase
- HMG-CoA Reductase
- Lactate Dehydrogenase
- Monoamine oxidase b
- NADPH Cytochrome P450 Oxidoreductase
- Nitric Oxide Synthase
- 2-Oxoglutarate Dehydrogenase
- Phenylalanine hydroxylase
- Sulfite Oxidase
- Thioredoxin Reductase
- Urate Oxidase
- Xanthine oxidoreductase
Let us discuss the above-mentioned oxidoreductase enzymes in detail.
Aromatase
Aromatase found in vertebrates is a key enzyme for the biosynthesis of estrogen from androstenedione and estradiol from testosterone. In humans, aromatase is present throughout the body and localized to the endoplasmic reticulum of the cell.
Choline oxidase
The choline oxidase enzyme catalyzes the reaction between two molecules of oxygen gas and choline to form two molecules of hydrogen peroxide and betaine aldehyde. Betaine aldehyde is an organic compound used by plants to adapt to temperature differences.
Laccase
Laccase is a multicopper oxidase enzyme. It is found in fungus and used for dye adsorption from polluted environments. Laccases also play a significant role in the paper, food, and textile industries.
Dihydrofolate reductase
The dihydrofolate reductase enzyme is present in all organisms and responsible for catalyzing the reduction of dihydrofolate to tetrahydrofolate.
This enzyme is used for synthesizing inhibitors used for cancer therapeutics.
Glutathione reductase
The glutathione reductase enzyme generates two molecules of reduced glutathione from oxidized glutathione.
Glutathione reductase plays a key role in preventing human cells from oxidative stress.
Glyceraldehyde-3-Phosphate Dehydrogenase
Glyceraldehyde-3-phosphate dehydrogenase is an important enzyme in glycolysis. It breaks down glucose for energy production.
It also plays a prominent role in plants and algae for the fixation of carbon dioxide into carbohydrates.
HMG-CoA Reductase
HMG-CoA reductase is an essential enzyme for cholesterol biosynthesis. Its activity is inhibited by statins. HMG-CoA reductase can be identified in the endoplasmic reticulum membrane.
Lactate Dehydrogenase
Lactate dehydrogenase is an essential enzyme for anaerobic respiration. It converts pyruvate to lactic acid in the absence of oxygen.
Also, it anaerobically converts NADH to NAD+.
Monoamine oxidase b
Monoamine oxidase b enzyme present in the outer membrane of mitochondria catalyzes the oxidative deamination of serotonin. To prevent neurological disorders, monoamine oxidase b is inhibited by deprenyl.
NADPH Cytochrome P450 Oxidoreductase
NADPH Cytochrome P450 Oxidoreductase enzyme was first identified by Horecker in 1950.
It plays an important role in embryogenesis and also increases the sensitivity of cancer cells to anticancer drugs.
Nitric Oxide Synthase
In cell communication and cell signaling, nitric oxide synthase plays a significant role. It catalyzes the formation of nitric oxide from L-arginine.
2-Oxoglutarate Dehydrogenase
2-oxoglutarate dehydrogenase is a multienzyme complex consisting of three monomers, viz; E1, E2, and E3. This enzyme plays a prominent role in lysine degradation, citric acid cycle, and tryptophan metabolism.
Phenylalanine hydroxylase
In the liver, phenylalanine is converted to tyrosine with the help of the phenylalanine hydroxylase enzyme. Dysregulation of this enzyme results in phenylketonuria due to the conversion of phenylalanine to phenylpyruvate.
Sulfite Oxidase
Sulfite oxidase enzyme is found in the liver, heart, and kidney and localized to cell mitochondria.
Sulfite oxidase is a homodimer that has two similar monomers. A point mutation in this enzyme causes neurological disorders.
Thioredoxin Reductase
Thioredoxin reductase enzyme is a member of the family of pyridine nucleotide disulfide oxidoreductases. It’s a homodimer with each subunit composed of alpha helices and beta sheets. It is identified in both prokaryotes and eukaryotes.
Urate Oxidase
Urate oxidase enzyme plays an important role in purine degradation. It catalyzes the oxidation of uric acid, thereby preventing uric acid buildup. It is not found in humans and higher apes.
Xanthine oxidoreductase
Xanthine oxidoreductase is a dimeric enzyme found in bacteria and eukaryotes. It is available in two interconvertible forms: xanthine oxidase and xanthine dehydrogenase.
What are oxidoreductase enzymes?
Oxidoreductase enzymes are one of the six major classes of enzymes, responsible for catalyzing oxidation and reduction reactions. The molecule donating electron also known as oxidant or electron donor gets oxidized and the molecule accepting electron also known as reductant or electron acceptor gets reduced in a redox reaction. The term ‘redox’ is interchangeably used for the oxidation-reduction reaction.
Oxidoreductase enzyme structure
Oxidoreductase enzyme structure mainly includes dimeric forms. Like all other enzymes, the primary structure of the oxidoreductase enzyme consists of amino acid sequences.
Oxidoreductase enzyme function
Oxidoreductase enzymes function as important biocatalysts in the pharmaceutical and agricultural sectors. These enzymes are involved in the synthesis of several therapeutic drugs such as: 3,4-dihydroxylphenyl alanine (DOPA) for treating Parkinson’s disease and boceprevir to treat chronic hepatitis C infection. Oxidoreductase enzymes present in plats play a crucial role in quantitative and qualitative productivity of crops. Also, glucose oxidase found in fungal species are used as preservatives in dairy products.
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Hi..I am Moumita Nath, I have completed my Master’s in Biotechnology. I always like to explore new areas in the field of Biotechnology.
Apart from this, I like to read, travel and listen to Music.