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Hydrogen peroxide is a chemical compound with the formula H 2 O 2. In its pure form, ... Hydrogen peroxide is found in biological systems including the human body.
Glutathione peroxidases use glutathione as an electron donor and are active with both hydrogen peroxide and organic hydroperoxide substrates. Gpx1 , Gpx2 , Gpx3, and Gpx4 have been shown to be selenium -containing enzymes, whereas Gpx6 is a selenoprotein in humans with cysteine-containing homologues in rodents.
The chemical reactions catalyzed by thyroid peroxidase occur on the outer apical membrane surface and are mediated by hydrogen peroxide. The "organification of iodine", the incorporation of iodine into thyroglobulin for the production of thyroid hormone, is nonspecific; that is, there is no TPO-bound intermediate, but iodination occurs via ...
Low levels of catalase may play a role in the graying process of human hair. Hydrogen peroxide is naturally produced by the body and broken down by catalase. Hydrogen peroxide can accumulate in hair follicles and if catalase levels decline, this buildup can cause oxidative stress and graying. [54]
Lipid peroxidation, or lipid oxidation, is a complex chemical process that leads to oxidative degradation of lipids, [1] resulting in the formation of peroxide and hydroperoxide derivatives. [2]
In mammals the source of hydrogen peroxide is one of the duox1 or duox2 enzymes which reduce dioxygen to H 2 O 2 by oxidizing NADPH. [25] In the laboratory the source of the hydrogen peroxide (H 2 O 2) usually is the reaction of glucose with oxygen in the presence of the enzyme glucose oxidase (EC 1.1.3.4) that also takes place in saliva.
In enzymology, a NADH peroxidase (EC 1.11.1.1) is an enzyme that catalyzes the chemical reaction. NADH + H + + H 2 O 2 NAD + + 2 H 2 O. The presumed function of NADH peroxidase is to inactivate H 2 O 2 generated within the cell, for example by glycerol-3-phosphate oxidase during glycerol metabolism or dismutation of superoxide, before the H 2 O 2 causes damage to essential cellular components.
2) anion radical into normal molecular oxygen (O 2) and hydrogen peroxide (H 2 O 2). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. [2] Hydrogen peroxide is also damaging and is degraded by other enzymes such as catalase.