Xylan

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Material type:	Polymer
Material group:	Hetero polysaccharide, branched Hemicelluloses
Monomer(s):	L-arabinofuranose D-glucoronic acid D-xylopyranose
Links:	alpha-(1-2) alpha-(1-3) beta-(1-3) beta-(1-4)
Origin of the polymer:	Natural
CAS-Number:	9014-63-5

Structure

Type I: (→3)-β-D-xylan(1→). Xylan is a hemicellulose. Only a portion of the xylose units are substituted, and the substitution is not regular.

Type II: (→4)-β-D-xylan(1→). Short side chains of one or more types as in arabinoxylans and (4-O-methyl)-glucoronoxylans. Different sidechains may be attached to the main chain (1→4)-β-D-xylopyranosyl. These sidechains are α-D-glucopyranosyluronic acid (or the 4-methyl ether) and/or α-L-arabinofuranosyl residues attached at O(2) and O(3), respectively. Only a portion of the xylose units are substituted, and the substitution is not regular [4]. The highest number of consecutive substitutions is 6 [4]. The xylan chain is normally linear, but occationally it may be branched. Degree of polymerization: 70-130 [1].

Chemical properties

Type I: Crystallographic data [6].

Type II: Very soluble in water [2].

Biological properties

Immunological activity::
The xylan-BSA conjugate does not react with the murine monoclonal antibody Mab MPG2 [3].

Molecular biology
10-35% inhibition on the restriction enzyme HindIII at 100 μg polysaccharide / μg λ DNA, and 100% inhibition at 500 μg polysaccharide / μg λ DNA [5].

Physical properties

Appearance
	Physical state @ 20°C:	Solid

Occurence, isolation & synthesis

Occurence
Type I: Caulerpa filiformis and related green algae [1].

Type II: Widespread in higher plants, most commonly as related heteroglycans [1].

References

1: Mark,H.F., Bikales,N.M., Overberger,C.G., Menges,G., Kroschwitz,J.I. Encyclopedia of Polymer Science and Engineering 2.ed.
(1988) John Wiley & Sons

2: León de Pinto,G., Martínez,M., Rivas,C. Chemical and Spectroscopic Studies of Cercidium praecox Gum Exudate
Carbohydr. Res. (1994) 260 17-25

3: Hirata,A., Adachi,Y., Itoh,W., Komoda,M., Tabata,K., Sugawara,I. Monoclonal Antibody to Proteoglycan Derived from Grifola frondosa (Maitake)
Biol. Pharm. Bull. (1994) 17 539-542

4: Reicher,F., Gorin,P.A.J., Sierakowski,M.-R., Corréa,J.B.C. Highly Uneven Distribution of O-Acetyl Groups in the Acidic D-Xylan of Mimosa scabrella (Bracatinga)
Carbohydr. Res. (1989) 193 23-31

5: Do,N., Adams,R.P. A simple technique for removing plant polysaccharide contaminants from DNA
Biotechniques (1991) 10 162-166

6: Sundararajan,P.R., Marchessault,R.H. Bibliography of crystal structures of polysaccharides 1977-1979
Adv. Carbohydr. Chem. Biochem. (1982) 40 381-399

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© Michael Pilgaard
Created: March 10, 2008