Far-ultraviolet optical activity of saccharide derivatives. II. Dextran, amylose, and mycodextran acetes; dextran and amylose xanthates

✍ Scribed by S. Mukherjee; A. Sarko; R. H. Marchessault

• Publisher: Wiley (John Wiley & Sons)
• Year: 1972
• Tongue: English
• Weight: 686 KB
• Volume: 11
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1972.360110123

✦ Synopsis

The ultraviolet ORI) and CI) spectra of amylose, dextran, and mycodextran acetates and some of their oligomers were recorded in trifluoroethanol solution in the 300-185 nm wavelength range. Similarly, the spectra of amylose and dextran xanthates in water solution were obtained in the 400-200 nm range. In the amylose acetate series, the monomer and dirner both show a normal acetyl n ---t ?r* transition in CD, while the trimer and the polymer both exhibit an additional, shorter wavelength peak. The latter is presumed to arise from a helical conformation of the amylose chain. This interpretation is substantiated by a helix-coil type transition of the CD spectra of amylose triacetate a t elevated temperatures and a reversion of the anomalous CD to the normal CD upon partial deacetylation. By contrast, neither dextran acetates nor mycodextran acetate exhibit any conformational effects. The CD of dextran acetates is quite sensitive to (3-1,6 and branch linkages. The OHD and CI> of amylose xanthate are complex, suggesting the presence of organized structure in solution. The dextran xanthate shows only a simple ORD spectrum and no observable CD.