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Hydrogen peroxide is a chemical compound with the formula H 2 O 2.In its pure form, it is a very pale blue [5] liquid that is slightly more viscous than water.It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use.
Hydrogen peroxide is a dangerously strong oxidant which must be immediately split into water and oxygen by the enzyme catalase. The conversion of 2× 2Carbon glycine to 1× C 3 serine in the mitochondria by the enzyme glycine-decarboxylase is a key step, which releases CO 2 , NH 3 , and reduces NAD to NADH.
Hydrogen peroxide is not nearly as reactive as these species, but is readily activated and is thus included. [3] Peroxynitrite and nitric oxide are reactive oxygen-containing species as well. Hydroxyl radical ( HO· ) is generated by Fenton reaction of hydrogen peroxide with ferrous compounds and related reducing agents:
This hydrogen peroxide then releases hydrogen peroxide: [(HO) 3 B(OOH)] − + H 2 O ⇌ B(OH) − 4 + H 2 O 2. Several metal hydroperoxide complexes have been characterized by X-ray crystallography. Some form by the reaction of metal hydrides with oxygen gas: [17] L n M−H + O 2 → L n M−O−O−H (L n refers to other ligands bound to the ...
The energy stored in the chemical bonds of glucose is released by the cell in the citric acid cycle, producing carbon dioxide and the energetic electron donors NADH and FADH. Oxidative phosphorylation uses these molecules and O 2 to produce ATP , which is used throughout the cell whenever energy is needed.
The free radicals generated by this process engage in secondary reactions. For example, the hydroxyl is a powerful, non-selective oxidant. [6] Oxidation of an organic compound by Fenton's reagent is rapid and exothermic and results in the oxidation of contaminants to primarily carbon dioxide and water.
Hydrogen peroxide is also damaging and is degraded by other enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen. One exception is Lactobacillus plantarum and related lactobacilli , which use intracellular manganese to prevent damage from reactive O −
Hydrogen peroxide exposure may also result in hypersensitive response, which is the death of a small number of host cells at the site of infection, for the purpose of limiting pathogenic infection. [ 30 ] [ 31 ] ROS production in plants can be used as a readout for successful pathogen recognition via a luminol - peroxidase based assay.