Levan

Main page

Chemistry • Periodic table • Polymers • Organic compounds • Inorganic compounds • R/S-phrases

Education • Main page • Innovation in R&D

The site • Disclaimer • About the site • Site history

Material type:	Polymer
Material group:	Homo polysaccharide, both linear and branched
Monomer(s):	D-fructofuranose
Links:	beta-(2-6)
Origin of the polymer:	Natural

Structure

(→6)-ß-D-fructofuranose(2→). Linkage distribution: grasses and cereals: mainly linear. Bacteria: some branching (5%-20% [2,3]) (2→1), unit chain lenght ~12 [1]. The molecule is globular [3], flexible and tend to be a left-hand twist [2].

Chemical properties

Usually af relatively low molecular weight for grasses and cereals [1].

Levorotary, amorphous or microcrystalline, with varying solubility in cold water, very soluble in hot water and insoluble in absolute ethanol [2].

Biological properties

Promotion of infection (at Mr>10⁷) and necrosis, tumor inhibition and stimulation, and increase in premeability for a cytotoxic agent. This is caused partly by suppression of normal inflammatory response. Natural levans are serologically active and elicit antibody production, but purified levan preparations are not antigenic [2].

Physical properties

Appearance
	Physical state @ 20°C:	Solid

Bulk properties
	Molecular weight (g/mol):	Approximately 1,000,000 for bacterias [1].

Occurence, isolation & synthesis

Occurence
Grasses, some cereals and bacterias [1]. Called phleins if the source is plants [2].

References

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

2: Y.W.Han. Microbial Levan
Adv. Appl. Microbiol. (1990) 35 171-94

3: P.J.Simms, W.J.Boyko, J.R.Edwards. The Structural Analysis of a Levan Produced by Streptococcus salivarius SS2
Carbohydr. Res. (1990) 208 193-98

---

© Michael Pilgaard
Created: March 6, 2008