Conformation of Some Hexuronic Acids and D-Galactopyranosiduronic Acid Moiety in the Peracetylated and Permethylated Derivatives of Orange Pectic Acid in Solution

Abstract

1. The IC conformation was estimated for α-D-galactopyranosiduronic acid moiety of pectic acid in the permethylated derivative dissolved in 1N NaOD-D₂O and in the per-acetylated derivative dissolved in dimethyl sulfoxide-d₆, and the Cl conformation was estimated for some derivatives of D-galactopyranuronic acid in chloroform-d by NMR spectroscopy.
2. Random conformation of the whole macromolecule was estimated for pectic acid in water on the basis of no appearance of any induced Cotton effects in the 200_??_700mμ region in the ORD spectra of pectic acid-anionic dye complexes.
3. The conformation was supported by the fact that the rate of periodate oxidation of pectic acid at 5° was slightly decreased in comparison with that of amylase in 7M urea solution.