A protease cleaves a polypeptide that it recognizes at a pen

A protease cleaves a polypeptide that it recognizes at a pentapeptide segment. Assuming that a hydrogen bond is worth 2 kJ/mol, how much energy can it release by perfectly binding the backbone within the pentapeptide (that is, the four paptides within the five amino-acid segment)? Only count H-bonds for this problem and only one H-bond per C=O group.

A) 4 kJ/mol

B) 8 kJ/mol

C) 16kJ/mol

D) 24 kJ/mol

E) 32 kJ/mol

Solution

Break down of each hydrogen bond corresponds to release of 2kJ/mol of energy. In a pentapeptide, there are 4 hydrogen bonds within five amino acid segment. Therefore, the energy released by protease is 4 x 2 = 8 kJ/mol. Option B is correct.