Biological synthesis of proteins

Much the same principle of carboxylate activation is applicable to the in vivo synthesis of proteins. Again the carboxylate of an amino acid becomes activated by reaction with ATP to form an anhydride intermediate. The next step does not simply involve attack of a second amino acid of this anhydride since the synthesis of a protein involves the precise sequential coupling of 

Activation of the amino acid by ATP is only an intermediate step catalyzed by the enzyme aminoacyl-tRNA synthetase. The 3 - or 2 -hydroxyl of the terminal adenylic acid of the tRNA molecule then attacks the anhydride intermediate to give an aminoacyl-tRNA molecule. 

The ester linkage between the hydroxyl of the tRNA is a high energy bond (due to the adjacent 2 -hydroxyl and cationic amino functions) so that the overall enzyme catalyzed reaction has a free energy change close to zero. Each amino acid has a specific tRNA molecule and one specific aminoacyl-tRNA synthetase enzyme. In turn, each aminoacyl-tRNA synthetase enzyme will accept only its particular amino acid as a substrate. However, it has been possible to slightly modify the naturally occuring amino acids and have them serve as substrates for the enzyme. For example, p-fluorophenylalanine can substitute to some extent for phenylalanine. 

Once synthesis of the aminoacyl-tRNA is complete, the amino acid no longer serves a recognition function. Specificity is dictated by the tRNA portion of the molecule by its interaction with the genetic message (mRNA) 

This was demonstrated by taking the aminoacyl-tRNA complex specific for cysteine (abbreviation, cysteinyl-tRNA showing that the cysteine has combined with its specific tRNA) and modifying the amino acid side chain to form alanine by catalytic reduction. 

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The earliest reported scientific studies of Maillard reactions were by Dr. Louis Camille Maillard in figure 2 (14) who, in an attempt to determine the biological synthesis of proteins, heated concentrated solutions of D-glucose and amino... 

The biological synthesis of proteins is central to so much chemical biology research today. Modern day biological synthesis of proteins requires that all proteins are purified from one organism or another. If particularly large quantities of proteins (mg-g levels) are required then recombinant techniques and the growth of recombinant factory organisms are often... 

In order to understand the biological synthesis of proteins, we must first learn about the basic building block called a nucleoside. A nucleoside is a p-glycoside... 

Biological synthesis of proteins is a complex process requiring ordered macromolecular surfaces, protein catalysts, energy storage forms, etc. This alone would indicate that the chemical synthesis of a protein would be a difficult undertaking. Therefore, a number of considerations must be made before attempting such a project. 

Formyl function may be used as a simple acyl protecting group, as was observed for the N-terminal amino acid in the biological synthesis of proteins. It may be removed under mildly acidic conditions that will not affect peptide bonds. 

Attention should be given to the similarity between solid phase technology and the biological synthesis of proteins. In both cases, an amino acid is attached via the carboxylate function to a large macromolecular surface upon which the sequential addition of other amino acids and peptide bond formation occurs. In one case, the polymer, like the tRNA molecule at the peptidyl site, is the leaving group, while in the other case, the polymer, like the tRNA molecule at the aminoacyl site, remains bound to the chain after formation... 

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