aminohappotähteeseen

Aminohappotähteeseen, often translated as amino acid residue, refers to the portion of an amino acid that remains after it has been incorporated into a peptide or protein through the formation of a peptide bond. When amino acids link together to form a polypeptide chain, the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. The remaining part of the amino acid, now connected to its neighbor via the peptide bond, is called an amino acid residue.

The term "residue" is used because the original amino acid has, in a sense, "left behind" a water molecule as part of the polymerization process. Therefore, a protein composed of 'n' amino acids will actually contain 'n' amino acid residues linked by 'n-1' peptide bonds. Each residue retains the characteristic side chain (R-group) of the original amino acid, which plays a crucial role in determining the protein's three-dimensional structure, chemical properties, and biological function. The sequence of these amino acid residues forms the primary structure of a protein, which is fundamental to its overall conformation and activity. Understanding amino acid residues is essential in fields like biochemistry, molecular biology, and protein engineering.