''N''-Acetylmuramic acid (NAM or MurNAc) is an organic compound with the chemical formula . It is a monomer of

peptidoglycan Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane, the rigid cell wall (murein sacculus) characteristic of most ba ...

in most

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

s, which is built from alternating units of ''N''-acetylglucosamine (GlcNAc) and ''N''-acetylmuramic acid, cross-linked by

oligopeptide An oligopeptide, often just called peptide ('' oligo-'', "a few"), consists of two to twenty amino acids and can include dipeptides, tripeptides, tetrapeptides, and pentapeptides. Some of the major classes of naturally occurring oligopeptides in ...

s at the

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as nat ...

residue of MurNAc. MurNAc is a

monosaccharide Monosaccharides (from Greek '' monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. They are usually colorless, water- so ...

derivative of ''N''-acetylglucosamine.

Formation of NAM

NAM is an addition product of

phosphoenolpyruvate Phosphoenolpyruvate (2-phosphoenolpyruvate, PEP) is the ester derived from the enol of pyruvate and phosphate. It exists as an anion. PEP is an important intermediate in biochemistry. It has the highest-energy phosphate bond found (−61.9 kJ/m ...

and ''N''-acetylglucosamine. This addition happens exclusively in the cell

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

Clinical significance

''N''-Acetylmuramic acid (MurNAc) is part of the peptidoglycan polymer of bacterial cell walls. MurNAc is covalently linked to ''N''-acetylglucosamine and may also be linked through the hydroxyl on carbon number 4 to the carbon of L-alanine. A pentapeptide composed of L-alanyl-D-isoglutaminyl-L-lysyl-D-alanyl-D-alanine is added to the MurNAc in the process of making the peptidoglycan strands of the cell wall. Synthesis of NAM is inhibited by fosfomycin. NAG and NAM cross-linking can be inhibited by

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and preventio ...

to inhibit pathogens from growing within the body. Therefore, both NAG and NAM are valuable polymers in medicinal research.

Formation of NAM

Clinical significance

References

See also