If, in a peptide chain, there were 85 amino acids each joined by peptide bonds, there would only be 1 N-terminus group that would be present. The N-terminus group is always the start of the chain of a amino acid chain or a protein or a polypeptide. It refers to the free amine group present that is located at the end part of the chain. So, that no matter how many amino acids in a chain there would always be only one N-terminus group.