Amino acid residues

From The School of Biomedical Sciences Wiki
Jump to: navigation, search

An amino acid residue is what an amino acid is known as once it has become a part of a polypeptide chain, once it has been joined to other amino acids in the chain by a peptide bond (resulting in the loss of a water molecule or a condensation reaction).

A residue has a alpha- carbon, a carbonyl group (C=O) and usually, in most cases, an NH group. Polypeptide chains can have as many as 50 - 2000 amino acid residues.

A sequence of amino acids in a polypeptide chain is written with the amino group at the beginning and in the direction of the carboxylic group, which results at the end Therefore, the amino acid at the beginning is known as the amino-terminal residue and the amino acid at the end of the chain is known as the carboxyl-terminal residue [1].


  1. Berg et al, Biochemistry, 6th Edition, New York, W.H. Freeman and Company, 2007

Personal tools