Translational diffusion coefficient of cycloamylose in aqueous sodium hydroxide

Abstract

Seven cyclic (1 --> 4)-alpha-D-glucan (cycloamylose) samples ranging in weight-average molecular weight from 5 x 10(3) to 1.8 x 10(4) and gamma-cyclodextrin have been studied by sedimentation equilibrium in dimethylsulfoxide (at 25 degrees C) and by dynamic light scattering in 0.5 N aqueous sodium hydroxide (at 25 degrees C), a good solvent for linear amylose. The measured translational diffusion coefficients D in the aqueous NaOH agree fairly closely with previous Monte Carlo results for cyclic (1 --> 4)-alpha-D-glucan chains with excluded volume, when correction is made for the effects of bead diameter and fluctuating hydrodynamic interaction (HI) on the Kirkwood theory on which the computation of D was based. These D data are also explained almost quantitatively by Yamakawa and Fujii's expression for the associated KP ring (based on the Kratky-Porod wormlike chain) with the molecular parameters for linear amylose if the fluctuating HI and excluded-volume effects are taken into account. It is concluded that the translational diffusion behavior of cycloamylose in the aqueous NaOH is consistent with the conformational characteristics derived from the conformational energy of maltose and dilute-solution data for linear amylose.

Linear and cyclic amylose derivatives having brush like side groups in solution: Amylose tris(n-octadecylcarbamate)s

“…Cyclic or ring polymers are much less investigated than the linear polymers owing to the difficulty to synthesize suitable model polymers. Chain conformation of cyclic DNA [17,27], cyclic polysaccharides [26,28,29], polystyrene [30][31][32][33][34][35], and polydimethylsiloxane [36] were reported other than above mentioned macrocyclic comb polymers. Only cyclic DNA behaves as rather rigid ring polymers while the other cyclic macromolecules have quite flexible main chain in solution.…”

“…Meanwhile, we recently prepared three kinds of cyclic amylose carbamate derivatives with phenyl [22], n-butyl [23], and 3,5-dimethylphenyl [24] side groups from enzymatically synthesized cyclic amylose (cESA), which has substantially no linear contamination [25,26].…”

Large-ring Cyclodextrins

“…Furthermore, the molecular structure was able to change easily to a variety of forms. Study of physicochemical properties based on the calculation of the diffusion coefficient on model chains generated by the Monte Carlo method and measurement were also carried out (43,44). The results mentioned above are important to understand the high water solubility of LR-CDs.…”

Hydrodynamic properties of cyclodextrin molecules in dilute solutions

“…CDs and their derivatives are considered to be potential carriers for hydrophobic pharmaceutical compounds (Loftsson and Duchene 2007; Uekama et al 1998). However, information about the properties of cyclodextrins molecules in diluted solution is still rather scarce (Dodziuk 2006; Nakata et al 2003; Longsworth 1953; Szejti 1998). …”