A -Acetylglucosamine

GalNAc, Gal, GlcNAc, Hex and HexNAc are the abbreviations used when discussing sequences of monosaccharides and represent A-acetylgalactosamine, galactose, A-acetylglucosamine, hexose, i.e. a monosaccharide with six carbon atoms, and A-acetylhexosamine, respectively. 

Fig. 8.1 Biosynthesis of peptidoglycan. The large circles represent A -acetylglucosamine orN-acetylmuramic acid to the latter is linked initially a pentapeptide chain comprising L-alanine, D-glutamic acid and meso-diaminopiraelic acid (small circles) terminating in two D-alanine residues (small, darker circles). The lipid molecule is undecaprenyl phosphate. In the initial (cytoplasm) stage where inhibition by the antibiotic D-cycloserine is shown, two molecules of Dalanine (small circles) are converted by an isomerase to the D-forms (small, darker circles), alter which a ligase joins the two D-alanines together to produce a D-alanyl-D-alanine dipeptide.

Tretter, V., Altmann, F. and Marz, L. (1991) Peptide-A74-(A-acetyl-P-glucosamiriyl) asparagine amidase F cannot release glycans with fucose attached al-3 to the asparagine-linked A-acetylglucosamin e residue. European Journal of Biochemistry 199, 647-652. 

Fig. 19.1. Structure of phosphorylcholine (PC). PC is involved in phosphodiester linkage to carbohydrate in a number of lower organisms, including filarial nematodes (linking sugar appears to be A/-acetylglucosamine on species examined to date).

Figure 2.7. The outer membrane of Gram-negative bacteria. Abbreviations LB, LamB protein LP, lipoprotein O, OmpA protein MP, membrane protein. The peptidoglycan backbone consists of alternating residues of A-acetylglucosamine and /V-acetylmuramic acid, which are cross-linked via short peptides.

Fig. 3. Difference spectra of the complex of lysozyme plus hexa-A-acetylglucosamine (hexa-NAG) vs native lysozyme at 20°C in various solvents.

---