The hydrodynamic behaviour of native amylose in good solvents

• Published in: Carbohydrate research 1968-08, Vol.7 (4), p.414-420
• Main Authors: Banks, W., Greenwood, C.T.
• Format: Article
• Language: English
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/S0008-6215(00)82960-2

Viscosity measurements on 12 fractions of linear amylose have been made in three thermodynamically good solvents—formamide (F), methyl sulphoxide (Me 2SO), and aqueous potassium hydroxide (KOH). The following Mark-Houwink relations were obtained: [ η ] F = 3.05 × 10 − 2 M ¯ ω 0.62 , [ η ] M e 2 S O = 1.51 × 10 − 2 M ¯ ω 0.70 , and [ η ] K O H = 8.36 × 10 − 3 M ¯ ω 0.77 . The Kamide-Inamoto and Stockmayer-Fixman-Burchard theories show that the amylose molecules in these solvents are extended as a result of solute-solvent interaction and there is little evidence of any free-draining characteristics. The graph of [η]/ M 1/2 against M 1/2 for all three good solvents is linear with a common intercept. Incidently, this intercept is the same as that for an aqueous theta-solvent, showing that the basic skeletal structure of amylose is the same in each of these solvents. The conformation of amylose in these three good solvents is regarded as being that of a random coil with negligible helical character.