N-terminal amino acid

Definition

The N-terminal amino acid is the first amino acid in a peptide or protein chain, characterized by having a free amine group (-NH2) that is not involved in a peptide bond. It indicates the starting point of the peptide or protein synthesis.

Related terms

Peptide bond:

A covalent chemical bond formed between two amino acids when the carboxyl group of one reacts with the amine group of another, releasing water.

C: terminal amino acid - The last amino acid in a peptide or protein chain, characterized by having a free carboxyl group (-COOH) that is not involved in a peptide bond.

Polypeptide:

A linear organic polymer consisting of a large number of amino-acid residues bonded together in a chain, forming part of (or the whole of) a protein molecule