polüpeptiidahelast

A polypeptide chain is a linear sequence of amino acids linked together by peptide bonds. These bonds are formed through a dehydration reaction, where a water molecule is removed as an amino acid joins the growing chain. The sequence of amino acids in a polypeptide chain is determined by the genetic code, specifically the messenger RNA (mRNA) transcribed from DNA. This sequence dictates the polypeptide's three-dimensional structure and, consequently, its function.

Polypeptide chains are the fundamental building blocks of proteins. While some proteins consist of a single polypeptide chain, many are composed of multiple polypeptide chains that associate to form a functional protein complex. The precise order of amino acids is crucial; a change in even a single amino acid can significantly alter the protein's structure and biological activity, sometimes leading to disease. The term polypeptide is often used to refer to a chain that has not yet folded into its final functional protein structure or to a shorter chain that may not be considered a fully functional protein on its own. The synthesis of polypeptide chains occurs during the process of translation, which takes place in ribosomes.