Poly -glucosamines

The most important of the poly(j8-glucosamines) found in nature have the 2-position hydroxyl groups in the glucose residue replaced by an amino group. They are, therefore, poly(j8-2-amino-2-deoxy-glucopyranoses). 

Chitin is poly[j5-(l- 4)-iV-acety 1-2-amino-2-deoxyglucopyranose]. The shells of crustaceans contain 20-25% chitin together with 70% calcium carbonate. It is the second most important biological animal structural material after the protein collagen. 

Chitin is obtained by first dissolving away the calcium carbonate with 5 % hydrochloric acid. Then any protein is removed with pepsin or trypsin. Next comes the deacetylation of the chitin to chitosan, whereby the enzymatic treatment is followed by using a 5 % caustic soda solution, followed by treatment with concentrated alkali in ethanol/ethylene glycol. 

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Fig. 183. Mannich bases as ion exchange resins derived from cellulose or poly(glucosamine).

This enzyme [EC 3.2.1.14] (also referred to as chitodex-trinase, l,4-j8-poly-A-acetylglucosaminidase, and poly-j8-glucosaminidase) catalyzes the hydrolysis of the l,4-j8-linkages of A-acetyl-D-glucosamine polymers of chitin. It should be noted that some chitinases will also display the activity observed with lysozyme [EC 3.2.1.17]. 

USEPA (2001) Chitin Poly-N-acetyl-o-glucosamine (128991) Fact Sheet http // www.epa.gov/oppbppdl/biopesticides/ ingredients / factsheets / factsheeCl 28991. htm (last accessed 30 April 2010). 

The /3(1— 4) linkage is relatively resistant to hydrolysis, so the major site of hydrolysis is that of the N-acetyl group to yield poly(ar-D-glucosamine) and acetic acid. This material is also known as chitosan . 

The polymer substrate consisted of low viscosity chitosan, poly(D-glucosamine), (I), which had a Brookfield viscosity of a 120-200 cps in 1% acetic acid solution. 

Chitin, poly-acetyl glucosamine shell protein poly-acetylglucosaminyl-transferase shell ming keratinocytes chitosan shell protein, p-farming chitina. 

In addition, a synthetic route was recently reported for /3-(l,6)-linked glucosamine oligosaccharides containing up to 11 glucosamine residues, corresponding to fragments of the extracellular polysaccharide poly-Af-acetylglucosamine, important in biofilm formation in many bacteria (O Fig. 27) [341]. 

Amino-2-deoxy-(l,4)-P-D-glucopyranan deacetylated chitin deacetylchitin P-l,4-poly-D-glucosamine poly-D-glucosamine poly-(l,4-P-D-glucopyranosamine). 

Fig. 5. Induction of poly-iV-acetyllactosamine expression in differentiating mouse neuroblastoma cells. N1E-115 neuroblastoma cells were grown in the undifferentiated form or induced to differentiate by serum starvation for ten days. The glycopeptides metabolically labelled with H-glucosamine were prepared by pronase digestion and fractionated by gel filtration on a column of Bio-Gel P-100. The poIy-fV-acetyllactosamine glycopeptides (poly-LacNAc) were eluted in the fractions indicated by the bar [39].

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