Description_x000D_ General description_x000D_ Peptidoglycan.is a biopolymer that is a major component of the cell walls of Gram-positive bacteria. Peptidoglycan consists of a carbohydrate backbone of alternating units of N-acetyl glucosamine and N-acetyl muramic acid and is modified with both D- and L-amino acids. N-Acetyl muramic acid residues are cross-linked with oligopeptides. The terminal peptide is D-alanine although other amino acids are present as D-isomers._x000D_ Application_x000D_ Peptidoglycan may be used for the activity estimation of lytic enzymes (e.g. lyticase). It is recommended to use a peptidoglycan concentration of 0.15-3 μg/ml in water or buffer and measuring at 450 nm. The peptidoglycan is not soluble but produces a suspension in water._x000D_ Peptidoglycan activates the Toll-like receptor 2 (TLR2), present in mammalian cells for the stimulation of lymphocytes. It may also function as an antagonist of Poly (I:C).