JEE Advanced levelOne or more correct optionsDifficulty 3 of 3bm106
The tetrapeptide Gly-Ala-Ser-Val is written from the N-terminal to the C-terminal end. Which statements are correct?
AUsing the same four different amino acids, 24 sequence isomers are possible.
BGlycine is the N-terminal residue.
CIt contains three peptide bonds.
DFour water molecules are lost when it is formed from the free amino acids.
Answer: A, B, C
A linear tetrapeptide has 4−1=3 peptide bonds and forms with the loss of 3 water molecules, not 4. Four different amino acids can be ordered in 4!=24 ways. Gly is on the left, so it is the N-terminal residue.