peptidoglycan

https://doi.org/10.1351/goldbook.P04480
A glycosaminoglycan formed by alternating residues of d-glucosamine and either muramic acid {2-amino-3-O-[(S)-1-carboxyethyl]-2-deoxy-d-glucose} or l-talosaminuronic acid (2-amino-2-deoxy-l-taluronic acid), which are usually N-acetylated or N-glycoloylated. The carboxyl group of the muramic acid is commonly substituted by a peptide containing residues of both l- and d-amino acids, whereas that of l-talosaminuronic acid is substituted by a peptide consisting of l-amino acids only.
Sources:
PAC, 1988, 60, 1389. 'Nomenclature of glycoproteins, glycopeptides and peptidoglycans (Recommendations 1985)' on page 1391 (https://doi.org/10.1351/pac198860091389)
White Book, 2nd ed., p. 85 (https://www.qmul.ac.uk/sbcs/iupac/bibliog/white.html)