oxidation

1. Combination with oxygen. 2. Increasing the valence of an atom or ion by the loss from it of hydrogen or of one or more electrons thus rendering it more electropositive, as when iron is changed from the ferrous (2+) to the ferric (3+) state. 3. In bacteriology, the aerobic dissimilation of substrates with the production of energy and water; in contrast to fermentation, the transfer of electrons in the o. process is accomplished via the respiratory chain, which utilizes oxygen as the final electron acceptor.

- alpha-o., α-o. a form of o. of fatty acid s in which carbons are removed one at a time in the form of CO₂; the α-carbon is first hydroxylated and then converted into a carbonyl; a deficiency of this pathway is associated with Refsum disease.

- beta-o., β-o. 1. o. of the β-carbon (carbon 3) of a fatty acid, forming the β-keto (β-oxo) acid analog; of importance in fatty acid catabolism; 2. the entire pathway for the catabolism of saturated fatty acid s containing an even number of carbon atoms; beta-o. (1) is a part of this pathway; acetyl-CoA is a major product of this pathway.

- end o. the last o. step in a catabolic pathway. SYN: terminal o..

- omega-o., ω-o. o. at the carbon atom farthest removed (ω-carbon) from the carboxyl group (carbon 1); thus, in this pathway, a dicarboxylic acid is formed; an important pathway in the degradation of prostaglandins.

- terminal o. SYN: end o..

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ox·i·da·tion .äk-sə-'dā-shən n

1) the act or process of oxidizing

2) the state or result of being oxidized

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ox·i·da·tion (ok″sĭ-daґshən) the act of oxidizing or state of being oxidized. Chemically it consists of the increase of positive charges on an atom or the loss of negative charges. Most biological oxidations are accomplished by the removal of a pair of hydrogen atoms (dehydrogenation) from a molecule. Such oxidations must be accompanied by reduction of an acceptor molecule. Univalent o. indicates loss of one electron; divalent o., the loss of two electrons.