peptidoglycosaminoglycan
peptidoglycosaminoglycan
A family of glycosaminoglycan formed by alternating residues of <small>D</small>-glucosamine and either muramic acid {2-amino-3-<em>O</em>-[(<i>S</i>)-1-carboxyethyl]-2-deoxy-<small>D</small>-glucose} or <small>L</small>-talosaminuronic acid (2-amino-2-deoxy-<small>L</small>-taluronic acid), which are usually <em>N</em>-acetylated or <em>N</em>-glycoloylated. Those containing muramic acid residues are known as peptidoglycans while those containing <small>L</small>-talosaminuronic acid residues are known as pseudopeptidoglycans. The carboxyl group of the muramic acid is commonly substituted by a peptide containing residues of both <small>L</small>- and <small>D</small>-amino acids, whereas that of <small>L</small>-talosaminuronic acid is substituted by a peptide consisting of <small>L</small>-amino acids only.