Transamination


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Transamination: deamination, Oxidative deamination

Transamination

The transfer of an amino group from one molecule to another without the intermediate formation of ammonia. Enzymatic reactions of this type play a prominent role in the formation and ultimate breakdown of amino acids by living organisms. Enzymes that catalyze such reactions are widely distributed and are termed transaminases, or amino-transferases. Perhaps the most prominent transamination reactions in higher animals are those in which glutamate is formed from α-ketoglutarate and other amino acids. See Protein metabolism

Transamination

 

a reversible transfer of an amino group (—NH2) from amino acids or amines to keto acids:

The enzymatic transamination reaction, which was discovered in 1937 by the Soviet biochemists A. E. Braunshtein and M. G. Kritsman, is an important link in the process of synthesis and deamination of many amino acids in animals, plants, and microorganisms. Most natural amino acids are synthesized in tissues by the transfer of an NH2 group from glutamic acid, the initial product of nitrogen assimilation, to various keto acids. By permitting rapid interconversion of the various amino and keto acids, the transamination reaction plays an important role in the regulation and coordination of the metabolism of amino acids and carbohydrates.

The enzymes for transamination, transaminases, are found in all living cells. There are more than 55 known transaminases, which catalyze the transamination of all the known natural amino acids and a number of biogenic amines. The coenzyme of transaminases is a derivative of vitamin B6, pyridoxal phosphate, which acts to transfer NH2 groups (for a discussion of the mechanism of transamination, see). A sharp increase in the content of some transaminases in the blood plasma of ill individuals is indicative of damage to the liver (hepatitis), the heart (myocardial infarction), or the muscles (trauma and myodystrophic diseases).

REFERENCES

Braunshtein, A. E., and M. M. Shemiakin. “Teoriia protsessov aminokislotnogo obmena, kataliziruemykh piridoksalevymi enzimami.” Biokhimiia, 1953, vol. 18, no. 4.
Meister, A. Biokhimiia aminokislot. Moscow, 1961. (Translated from English.)
The Enzymes, vol. 9. New York, 1973.

IU. M. TORCHINSKII

transamination

[tran‚sam·ə′nā·shən]
(chemistry)
The transfer of one or more amino groups from one compound to another.
The transposition of an amino group within a single compound.
References in periodicals archive ?
Two combinations of gluconeogenic precursors--glycerol+lactate and alanine+glutamine--were employed, the second one being dependent on liver nitrogen disposal by transamination or ureagenesis.
Above 280[degrees]C, an exothermal reaction starts, with a decrease of mass, which corresponds to the reaction of transamination. The sudden mass loss is produced by the higher mass of the ammonia product (N[H.sub.3]).
Increased transaminations during pesticide challenge have attributed to the need to meet higher energy demand by fish (Saravanan et al., 2012) Increased activities of these parameters were also observed in common carp, Cyprinus carpio exposed to the herbicide, Gordoprin Plus, with triazine and S-metalochlor as active ingredients (Dobsikova et al., 2011) and in other fish exposed to different environmental toxicants (Prusty et al., 2011; Saravanan et al., 2012).
SO[sub]2 has been considered harmful to the human body, but recently, there has been increasing interest in the physiological and pathophysiological roles of SO[sub]2 as a gaseous signaling molecule in the cardiovascular system, with functions such as inhibiting smooth muscle cell proliferation, relaxing blood vessels, reducing vascular inflammation and oxidative stress, and protecting myocardium.[sup][15],[16] Our previous research demonstrated that SO[sub]2 could be endogenously generated in vascular tissues from sulfur-containing amino acid metabolism through transamination, and it could regulate vascular activities.[sup][17],[18] However, the mechanisms underlying the inhibition of smooth muscle cell proliferation by SO[sub]2 have not been fully elucidated.
Therefore, salinity could inhibit the transamination reactions and hence the glutamic acid is accumulated and transformed to other nitrogenous compounds such as proline and ornithine.
Trophic enrichment of [delta][sup.15]N is generally attributed to fractionation during amino acid deamination and transamination (Vander Zanden & Rasmussen 2001), whereby the [sup.14]N amine groups are preferentially removed to produce isotopically light metabolites, leaving the remaining nitrogen pool enriched in [sup.15]N ("metabolic fractionation") and a more enriched signal for carnivores (Gannes et al.
(16-18) If nitrogenous compounds are lacking in the must (ammonia or free amino nitrogen), the yeast will be forced to scavenge nitrogen from available amino acids, and the transamination process will leave behind fusel alcohols as a byproduct.
Transamination, results in the formation of cathinone.
Transamination from Phe yields phenylpyruvic acid, of which as much as 1-2 g/day may be excreted in the urine.
This assumption is also favored by the tendency to some increase toward transamination enzymes activity in blood of bull-calves in experimental groups; so, index of alanine aminotransferase (ALT) exceeded that in the reference group by 3.6-9.9%, and serum glutamic oxalacetic transaminase (AST)--by 3.6-7.1%.