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Image File history File links Hydroxyl. ...
Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. Organic molecules containing a hydroxyl group are known as alcohols (the simplest of which have the formula CnH2n+1-OH). In organic chemistry functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ...
In organic chemistry, a substituent is an atom or group of atoms subsituted in place of a hydrogen atom on the parent chain of a hydrocarbon. ...
An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with the exception of carbides, carbonates, carbon oxides and gases containing carbon. ...
In chemistry, an alcohol is any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom of an alkyl or substituted alkyl group. ...
An Alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ...
Hydroxyl radical The hydroxyl radical, ·OH, is the neutral form of the hydroxide ion. Hydroxyl radicals are highly reactive and consequently short lived, however they form an important part of radical chemistry. Most notably hydroxyl radicals are produced from the decomposition of hydro-peroxides (ROOH) or, in atmospheric chemistry, by the reaction of excited atomic oxygen with water. Hydroxide is a functional group consisting of oxygen and hydrogen: -O−H It has a charge of 1-. The term hydroxyl group is used when the functional group -OH is counted as a substituent of an organic compound. ...
In chemistry, radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. ...
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Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earths atmosphere and that of other planets is studied. ...
Atmospheric importance The Hydroxyl radical is often referred to as the "detergent" of the troposphere because it reacts with many pollutants, often acting as the first step to their removal. The first reaction with many volatile organic compounds (VOCs) is the removal of a hydrogen atom forming water and an alkyl radical (R·). The Troposphere is the lowermost portion of Earths atmosphere. ...
Volatile organic compounds (VOCs) are organic chemical compounds that have high enough vapour pressures under normal conditions to significantly vaporize and enter the atmosphere. ...
An Alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ...
- OH + RH → H2O + R·
The alkly radical will typically react rapidly with oxygen forming a peroxy radical. - R· + O2 → RO2
The fate of this radical in the troposphere is dependent on factors such as the amount of sunlight (light from the sun), pollution in the atmosphere and the nature of the alkyl radical which form it.
Biological significance The hydroxyl radical has a very short in vivo half-life of approx. 10-9 s and a high reactivity. This makes it a very dangerous compound to the organism. Unlike superoxide, which can be detoxified by superoxide dismutase, the hydroxyl radical cannot be eliminated by an enzymatic reaction, as this would require its diffusion to the enzyme's active site. As diffusion is slower than the half-life of the molecule, it will react with any oxidizable compound in vicinity. It can damage virtually all types of macromolecules: carbohydrates, nucleic acids (mutations), lipids (lipid peroxidation) and amino acids (e.g. conversion of Phe to m-Tyr and o-Tyr)The only means to protect important cellular structures is the use of antioxidants such as glutathione and of effective repair systems. In vivo (Latin for (with)in the living). ...
Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...
Schematic electron configuration of superoxide. ...
Superoxide dismutase The enzyme superoxide dismutase (SOD, EC 1. ...
Ribbon diagram of the enzyme TIM. TIM is catalytically perfect, meaning its conversion rate is limited, or nearly limited to its substrate diffusion rate. ...
In biology, mutations are changes to the genetic material (usually DNA or RNA). ...
Lipid peroxidation refers to the oxidative degradation of lipids. ...
The amino acid Phenylalanine exists in two forms, the D- and L- forms. ...
Týr, depicted here with both hands intact, is identified with Mars in this illustration from an 18th century Icelandic manuscript. ...
Týr, depicted here with both hands intact, is identified with Mars in this illustration from an 18th century Icelandic manuscript. ...
It has been suggested that extracellular be merged into this article or section. ...
An antioxidant is a chemical that prevents the oxidation of other chemicals. ...
Glutathione (GSH), whose IUPAC name is 2-amino-5-{[2-[(carboxymethyl)amino]-1-(mercaptomethyl)-2-oxoethyl]amino}-5-oxopentanoic acid, is γ-glutamylcysteinylglycine, a tripeptide. ...
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