Deamination


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Related to Deamination: transamination, Oxidative deamination

deamination

[dē‚am·ə′nā·shən]
(organic chemistry)
Removal of an amino group from a molecule.

Deamination

 

the elimination of an amino group (NH2) from organic compounds. Deamination is accompanied by the substitution of some other group, such as H, OH, OR, or Hal, for the amino group or by the formation of a double bond. In particular, deamination is brought about by the action of nitrous acid on primary amines. In this reaction, acyclic amines yield alcohols (I) and olefins (II), for example:

The deamination of alicyclic amines is accompanied by ring expansion or contraction. In the presence of strong inorganic acids, aromatic amines and nitrous acid yield diazonium salts. Such reactions as hydrolysis, hydrogenolysis, decomposition of quaternary ammonium salts, and pyrolytic reactions also result in deamination.

Deamination plays an important part in the life processes of animals, plants, and microorganisms. Oxidative deamination, with the formation of ammonia and α-keto acids, is characteristic of d-amino acids. Amines also undergo oxidative deamination. Except for glutamate dehydrogenase, which deaminates L-glutamic acid, oxidases of natural amino acids are not very active in animal tissues. Therefore, most L-amino acids undergo indirect deamination by means of prior transamination, with the formation of glutamic acid, which then undergoes oxidative deamination or other transformations. Other types of deamination are reductive, hydrolytic (deamination of amino derivatives of purines, pyrimidines, and sugars), and intramolecular (histidine deamination), which occur mainly in microorganisms.

REFERENCE

Zbarskii, B. I., I. I. Ivanov, and S. R. Mardashev. Biologicheskaia khimiia, 4th ed. Leningrad, 1965.
References in periodicals archive ?
formation of carbocations from the deamination of N-substituted
Peptides containing N, Q, or M may be subject to deamination and oxidation and may affect sample stability.
Oxidative deamination of monoamines by the flavoenzyme MAO-A proceeds in two steps: in the first step, binding of the monoamine to the enzyme (E) yields an aldehyde and ammonia by reduction of FAD cofactor; in the second step, the oxidized form of the prosthetic group is restored by the binding of oxygen and the concomitant production of hydrogen peroxide ([H.sub.2][O.sub.2]).
Considering this characteristic, it is expected an inhibition of proteolytic bacteria through the inclusion of propolis in the animal diet (Hino & Russell, 1987) and, as consequences, an inhibition of protein deamination, proteolysis and production of gases, providing an increase of alimentary efficiency and feed digestibility (Aguiar et al., 2012; Prado, 2010a, c; Zawadzki et al., 2011a).
These products progenitors are highly genotoxic, the deamination of guanine, cytosine and adenine is mediated primarily by the N2O3 [10].
The primary enzyme for the metabolism of histamine is di-amine oxidase (DAO) (Maintz & Novak, 2001), which degrades extracellular histamine through oxidative deamination (NCBI).
Wu et al., "Nitric oxide turn-on fluorescent probe based on deamination of aromatic primary monoamines," Inorganic Chemistry, vol.
Techniques based on DNA modification by sodium bisulfite are unable to distinguish between methylation and hydroxymethylation, since both 5-mC and 5-hmC do not undergo deamination after reacting with sodium bisulfite, and 5-mC and 5-hmC contents are mixed up in the final results.
They hypothesized this was a result of deamination, a process they say is "highly efficient if melamine is used as the sole nitrogen source." But production was sharply reduced when a second nitrogen source--a soy broth--was present.
PLP is the active coenzyme product of the vitamin B6 pathway and is essential in many biochemical reactions, including decarboxylation, transamination, deamination, racemization and trans-sulfuration reactions associated primarily with amino acid synthesis [12].
These free radicals react with organic materials and phospholipids to cause lipid peroxidation, fragmentation of proteins and deamination of guanine and adenine in DNA chain to cause gene mutation and cell damage.6
Monoamine oxidases (MAO) A and B are located on the outer membrane of the mitochondria inside most neurons, including those of the sympathetic pathway, where they are responsible for the oxidative deamination of monoamines such as NA and adrenaline into the corresponding aldehyde and ammonia.