The N - terminus (also known as the amino - terminus, NH - terminus, N - terminal end or amine - terminus) is the start of a protein or polypeptide referring to the free amine group (- NH) located at the end of a polypeptide. Normally the amine group is bonded to another carboxylic group in a protein to make it a chain, but since the end of a protein has only 1 out of 2 areas chained, the free amine group is referred to the N - terminus. By convention, peptide sequences are written N - terminus to C - terminus, left to right in LTR languages. This correlates the translation direction to the text direction (because when a protein is translated from messenger RNA, it is created from N - terminus to C - terminus - amino acids are added to the carbonyl end).
what is n and c terminus in protein
amino acids