ATP and the biosynthesis of proteins

The function of adenosine triphosphate, ATP (Atlas N3) or (more succinctly) ATP, is to store the energy made available when food is oxidized and then to supply it on demand to a wide variety of processes, including muscular contraction, reproduction, and vision. We saw in Case study 2.2 that the essence of ATP s action is its abiUty to lose its terminal phosphate group by hydrolysis and to form adenosine diphosphate, ADP (Atlas N2)  

This reaction is exergonic under the conditions prevaiUng in cells and can drive an endergonic reaction forward if suitable enzymes are available to couple the reactions. One reason why ATP is so potent is that its concentration in cells is high, so its chemical potential is also high. 

In a moderately small protein such as myoglobin, with about 150 peptide links, the construction alone requires 450 ATP molecules and therefore about 12 mol of glucose molecules for 1 mol of protein molecules. 

Glycolysis occurs in the cytosol, the aqueous material encapsulated by the cell membrane, and consists of 10 enzyme-catalyzed reactions (Fig. 4.13). 

From now on, we shall represent biochemical reactions with chemical equations written with a shorthand method, in which some substances are given nicknames and charges are not always given explicitly. 

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