D-Muramic acid

Murein Bacterial cell wall N-acetyl-D-Glucosamine + N-acetyl-D-Muramic acid pi,4 ... 

There are several polysaccharides containing the /1-(1 4) stracture, but with monomer residues other than D-glucop)ranose, such as )V-acetyl-D-glucosamine, D-glucosamine, iV-acetyl-D-muramic acid. 

Properties and Occurrence of yv-Acetyl-o-Glucosamine and yV-Acetyl-D-Muramic Acid in Murein - The Bacteriai Ceii Waii... 

The major component of all known bacterial cell walls is a polysaccharide composed of Af-acetyl-D-glucosamine (NAG) linked together by 8-(l— 4) glycosidic bonds, as in chitin, but with every other NAG residue substituted at C-3 by an ether linkage to the hydroxyl group of L-lactic acid to give N-acetyl-D-muramic acid (NAM) [85,86,87,88]. This results in a nine-... 

A large number of bacterial polysaccharides are known [104]. The major structural component of the bacterial cell wall is a polysaccharide, known as murein and composed of a repeating unit of one A-acetyl-D-glucosamine and an O-lactyl substituted IV-acetyl-D-glucosamine (A-acetyl-D-muramic acid) see Sect. 7.3. 

Acetronitrile-acetic acid-ethanol-water Methanol-acetone 13 1 2 4 5 1 GlcN, GalN. ManN. D-muramic acid GlcN-HCl. ManN-HCl. GalN-HCl. GlcNAc Polysaccharide hydrolysates Ninhydrin. AgNO N inhydrin TLC What. K-5 MD. 3 runs 27 40... 

Figure 6.21. (continued) D, glycerol teichoic acid attached to murein chain at C-6 of A -acetyl-D-muramic acid E, O-phospho-D-mannan. 

Biosynthesis of N-acetyl-D-muramie acid by N-acetyi-D -muramic acid synthase... 

The bacterial cell wall peptidomurein is hydrolyzed by hen egg-white lysozyme [53] to give di-, tetra-, and octasaccharides by the specific hydrolysis of the glycosidic bond of A -acetyl-D-muramic acid [53]. Lysozyme will also hydrolyze the P-1 4 GlcNAc bond of chitin, but at a much lower rate. There are specific chitinases that will also hydrolyze chitin to give chitobiose and chitodex-trins. 

The presence of A-glycoIyl-D-muramic acid has been reported recently in bacterial cell walls (Adam et aL, 1969). 

It is interesting to note that the C-0 of an amino sugar residue absorbed on subsite D would lie very close to amino acid residue 52 of muramidase (Blake el al., 1967b), so that it is perliaps not. surprising that acetyl and other substituents at C-6 of muramic acid moieties prevent the action of the enzyme (Work, 1967). However, an mdomuramidase from the fungus Chalaropsis sp. has been designated X,0-diacetylmuramidase since it attacks 6-0-acetylatcd X-acetyl-D-muramic acid residues in bacterial cell wall preparations Mitchell and Hash, 1969 Browder et al, 1905). 

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