The Introduction of Redox Enzyme
Redox enzymes are a general term for enzymes that catalyze the redox between two molecules. Among them, oxidase can catalyze the oxidation of substances by oxygen, and dehydrogenase can catalyze the removal of hydrogen from material molecules. Numerous redox enzymes in organisms require coenzyme NAD or NADP as well as FAD or FMN when reacting. Of course, some enzymes do not require a coenzyme or a prosthetic group, and directly use oxygen as a carrier of electrons, such as glucose oxidase. The process of redox reaction in a living body has a movement of a pair of hydrogen atoms, the transfer of electrons, or an oxygen atom addition. A substance giving electrons or H to oxidize is called an electron donor or a hydrogen donor. A substance that acts as an oxidant and accepts electrons or hydrogen and is itself reduced is called an electron acceptor or a hydrogen acceptor.
The Research Status of Redox Enzyme
Oxidoreductases can now be classified into the following five categories, polyphenol oxidase, glucose oxidase, peroxidase, lipoxygenase, and superoxide dismutase. Polyphenol oxidase is widely present in various plants and is a copper-containing enzyme. Polyphenol oxidase can be divided into the following three major categories, monophenol oxidase, bisphenol oxidase and laccase. Polyphenol oxidase can catalyze the hydroxylation of monohydric phenols in the body to form corresponding ortho-dihydroxy compounds, and ortho-dihydroxy oxidized to form orthoquinones. These orthoquinones interact in the body to form high molecular polymers, and the formation of these high molecular polymers leads to the formation of brown pigment. The action of polyphenol oxidase leads to the formation of browning and dark spots of bananas, apples, and peaches. Some laboratories are now working on inhibitors of polyphenol oxidase to slow the browning process. Glucose oxidase is present in Aspergillus niger, Aspergillus oryzae and Penicillium, and glucose oxidase has not been found in higher plants and animals. In the body, it mainly catalyzes the conversion of glucose to gluconic acid, and with the formation of hydrogen peroxide, it plays an important role in the fermentation process of microorganisms. Peroxidase can be divided into the following three parts according to the specificity of the catalytic substrate, guaiacol peroxidase, glutathione peroxidase, and ascorbate peroxidase. In plants, peroxidase can oxidize indole acetic acid, and participate in the growth regulation of plants. Glutathione peroxidase (GSH-Px) is an important peroxide-degrading enzyme widely present in the body. Selenium is a component of the GSH-Px enzyme system, which catalyzes the conversion of GSH to GSSG, reduces toxic peroxides to non-toxic hydroxy compounds, and promotes the decomposition of H2O2, thereby protecting the structure and function of cell membranes from the interference and damage of peroxides. Fatty acid synthase (LOX) is mainly involved in the following reactions, reduction, isomerization of hydrogen peroxide linoleic acid, decomposition of hydrogen peroxide linoleic acid, and production of acetic acid. Therefore, LOX is involved in the processes of plant growth, development, maturation and senescence, especially the production of free radicals and biosynthesis of ethylene during mature senescence. Superoxide dismutase (SOD), a metal-containing enzyme, can be classified into iron type SOD, copper type SOD, and manganese type SOD. SOD can catalyze the disproportionation of superoxide anion and remove superoxide that is harmful to the body. SOD is the only enzyme that can scavenge free radicals in cells. The free radicals are electrons with unpaired electrons, atoms or ions, which are chemically active and have extremely high oxidizing properties to capture the electron from nucleic acids, amino acids and other biomolecules, then led them turn into more toxic hydroxyl radicals, which can cause a variety of diseases in the body. Studies have shown that SOD has unique effects on stomach diseases, bronchitis, skin diseases, burns and so on.