Analysis of the conformational properties of κ- and ι-carrageenan by size-exclusion chromatography combined with low-angle laser light scattering

✍ Scribed by Torgeir Hjerde; Olav Smidsrød; Bjørn E. Christensen

• Publisher: Wiley (John Wiley & Sons)
• Year: 1999
• Tongue: English
• Weight: 183 KB
• Volume: 49
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(199901)49:1<71::aid-bip7>3.0.co;2-h

✦ Synopsis

The conformational properties of -carrageenan in 0.2M LiI and -carrageenan in 0.2M LiCl were analyzed by size exclusion chromatography combined with low-angle laser light scattering. Fractionated samples with narrow molecular weight distributions (M w /M n ϳ 1.4) were used, and M w in the disordered states were 35,000 (-35) and 200,000 (-200) for -carrageenan and 65,000 (-65) and 170,000 (-170) for -carrageenan, respectively. The analyses were performed across a temperature range where the conformational transitions occurred, and at extremely low concentrations (2-50 g/mL) due to low amounts of samples injected and the subsequent dilution occurring during the separation. The results indicate that a twofold increase of the molecular weight (M w ) occurs for -carrageenan upon inducing the ordered conformation. For -carrageenan an additional increase in M w may take place, which is attributed to the strong tendency for aggregation of ordered chains especially at high molecular weights. The results thus suggest that bothand -carrageenan are double (or multiple) stranded in their ordered conformations, within the concentration range studied here.