Peptidoglycans, also called mureins, are polymers that makes up the cell wall of most bacteria, but can also be found in certain mushrooms.

It is made up of sugars and amino acids, and when many molecules of peptidoglycan joined together, they form an orderly crystal lattice structure.

Bacteria are classified as being either Gram-positive or Gram-negative based on differences in the structure of their peptidoglycan cell wall.

Archaea do not have a cell wall consisting of peptidoglycan, but some do have a layer of pseudopeptidoglycan (pseudomurein), which a is similar polymer.

Peptidoglycans in mushrooms

Some peptidoglycans are present in mushrooms: various bioactive peptidoglycans have been isolated from Ganoderma lucidum, including G. lucidum proteoglycan (GLPG; with antiviral activity, G. lucidum immunomodulating substance (GLIS, PGY (a water-soluble glycopeptide fractionated and purified from aqueous extracts of G. lucidum fruit bodies, GL-PS peptide (GL-PP, and F3 (a fucose-containing glycoprotein fraction.

Also, for example, LZ-B-1, water-soluble peptidoglycan, has shown a strong immunomodulatory activity.

In vitro experiments showed that LZ-B-1 promoted the proliferation of mouse spleen lymphocytes (MSLs) with an optimum concentration of 200 µg/mL.

Generally, the higher the mouse spleen cell proliferation rate, the stronger the immunomodulatory activity, therefore the peptidoglycan LZ-B-1 had an immunomodulatory effect.


  • Ye L.B., Zheng X.L., Zhang J.S., Yang Y., Meng Y.C., Li J.R., Chen W., Li A., Pan Y.J. Composition analysis and immunomodulatory capacity of peptidoglycan from Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W. Curt.: Fr.) P. Karst. Strain 119 (Aphyllophoromycetideae) Int. J. Med. Mushrooms. 2010;12:157–165. doi: 10.1615/IntJMedMushr.v12.i2.60.