Question

How many ATP and GTP molecules are required respectively for incorporation of 25 amino acids in peptide chain?

• A. 20 ATP, 20 GTP
• B. 25 ATP, 25 GTP
• C. 50 ATP, 50 GTP
• D. 25 ATP, 50 GTP

Answer 1

The correct option is D 25 ATP, 50 GTP

One GTP is hydrolyzed to GDP as each successive amino acid-tRNA complex attaches to the A site of the ribosome. A second GTP is broken down to GDP as the ribosome moves to each new codon in the mRNA. One ATP is hydrolyzed to AMP during amino acid activation. Thus, the formation of each peptide bond uses 3 high-energy molecules, one ATP and two GTP.

So, the correct answer is option D.