Energy, activation phosphate bond, utilization

How many high-energy phosphate-bond equivalents are utilized in the process of activation of amino acids for protein synthesis ... 

It was evident from early studies that in the presence of CoASH, ATP could in some way be used to activate acetate so that it will acetylate sulfanilamide (7) and choline (8). Chou and Lipmann (9) succeeded in partially purifying the enzyme(s) responsible for this activation from pigeon-liver extracts and they concluded that the phosphate bond energy of ATP is utilized to bring about the synthesis of acetyl coenzyme A (acetyl-SCoA) however, the mechanism of this activation remained obscure. The nature of the over-all process was further elucidated through the experiments of Lipmann et al. (10) who demonstrated that ATP, CoASH, and acetate react to form acetyl-SCoA, AMP, and inorganic pyrophosphate (P-P) in stoichiometric amounts [reaction (4)]. They also demonstrated that the reaction is freely reversible. More recently, the studies of Jones et al. (11) have indicated that the mechanism of this conversion is as follows ... 

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