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Transamidation is a chemical reaction in which an amide reacts with an amine to generate a new amide: RC(O)NR' 2 + HNR" 2 → RC(O)NR" 2 + HNR' 2 The reaction is typically very slow, but it can be accelerated with Lewis acid [ 1 ] and organometallic catalysts . [ 2 ]
Transamination is mediated by several types of aminotransferase enzymes. An aminotransferase may be specific for an individual amino acid, or it may be able to process any member of a group of similar ones, for example the branched-chain amino acids, which comprises valine, isoleucine, and leucine.
In organic chemistry, transamidification is the process of exchanging the subunits of a peptide, amide or ester compound with another amine or fatty acid to produce a new amide or peptide. The process has been used for the production of emulsifiers and dispersing agents [ 1 ] and oil drilling fluids.
Nine transglutaminases have been characterised in humans, [5] eight of which catalyse transamidation reactions. These TGases have a three or four-domain organization, with immunoglobulin-like domains surrounding the central catalytic domain.
The Beckmann rearrangement, named after the German chemist Ernst Otto Beckmann (1853–1923), is a rearrangement of an oxime functional group to substituted amides. [1] [2] The rearrangement has also been successfully performed on haloimines and nitrones.
Cancer cells can be killed by increasing calcium levels through the activation of tTG transamidation activity. Preclinical trials have showed promise in using tTG inhibitors as anti-cancer therapeutic agents. [38] However, other studies [33] have noted that tTG transamidation activity could be linked to the inhibition of tumor cell invasiveness.
Weinreb and Nahm originally proposed the following reaction mechanism to explain the selectivity shown in reactions of the Weinreb–Nahm amide. Their suggestion was that the tetrahedral intermediate (A below) formed as a result of nucleophilic addition by the organometallic reagent is stabilized by chelation from the methoxy group as shown. [1]
All together, the actual stability of the ester bond influences the susceptibility of the aa-tRNA to hydrolysis within the body at physiological pH and ion concentrations. It is thermodynamically favorable that the aminoacylation process yield a stable aa-tRNA molecule, thus providing for the acceleration and productivity of polypeptide synthesis.