ISSN:
0022-3832
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Living cultures of Aerobacter levanicum, or cell-free extracts on sucrose, elaborate levan, a polymer of D-fructose. Exhaustive methylation of the fructosan-culture levan, and the levan produced in vitro with dimethyl sulfate and sodium hydroxide yielded fully methylated trimethyllevan, which afforded on hydrolyses 1,3,4,6-tetra-,1,3,4-tri-, and 3,4-di-O-methyl-D-fructose in the molar ratio 1 : 7 : 1, respectively. These results indicate that the levan polymers are branched: main linkage C-2,6; branch linkage C-2,1; average basal chain length 9. The structural similarity of culture and “enzyme” levan was confirmed by infrared analysis. Partial hydrolyzates of levan examined chromatographically were found to contain more than one oligosaccharide at each level of DP above three. This observation is further evidence for branching in the native molecule. Oligosaccharides of DP 2-10 prepared by mild (2.5%) and extensive (66%) hydrolyses of the native polymer were all totally hydrolyzed to fructose by yeast invertase. This suggests that all the linkages in the levan molecule-both those at the chain terminals and those within the chains-are of the β-fructofuranosyl type. Diffusion and sedimentation measurements on levan provided values from which average molecular weights were calculated. Studies of the use of degraded levan preparations as plasma volume expanders are in progress.
Zusätzliches Material:
1 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1957.1202310421
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