Cyclic Peptide

Cyclic Peptide Cyclic peptides (or cyclic proteins) are polypeptide chains wherein the amino termini and carboxyl termini, amino termini and side chain, carboxyl termini and side chain, or side chain and side chain are linked with a covalent bond that generates the ring. Their length ranges from just two amino acid residues to hundreds. A number of cyclic peptides have been discovered in nature and a plethora have been synthesized in the laboratory. Hundreds Н, N. HN NH These cyclic peptides have several applications in medicine and biology. НО HN OH/H н N. NH Medicine Biology NH2 Classification of cyclic peptides Cyclic peptides can be classified according to the types of bonds that comprise the ring. Homodetic cyclic peptides, Such as cyclosporine A, are those in which the ring is composed exclusively of normal peptide bonds Cyclic isopeptides contain af least one non-alpha amide linkage, such as a linkage between the side chain of one residue to the alpha carboxyl group of another residue, as in microcystin and bacitracin. (i.e. between the alpha carboxyl of one residue to the alpha amine of another). Cyclic depsipeptides, Such as aureobasidin A and HUN-7293, have at least one lactone (ester) linkage in place of one of the amides. Bicyclic peptides such as the amatoxins amanitin and phalloidin contain a bridging group, generally between two of the side chains. Biosynthesis and applications One interesting property of cyclic peptideš is that they tend to be'extremely resistant to the process of digeștion, enabling them to survive in the human digestive tract The barr secte Live clee prde Pransin dicssdag mes are Amire acis ara absorpec rcm he smalimasaine in te bced stre Fiesine I tesal Iesine varcty broe pendes of dicsary proncin pondes, ancthen inciis al Issued by Blue Sky Peptide