Light scattering of rriulticliain poly-a-amino acids was studied in ditiietliylforInaniiclt: (DMF). The polymers consisted of a backbone of poly-rTlysine of degree of polymerization n with side chains of benzyl Gglutamate and benzyl Gaspartate of degree of polymerization, m, on each +amino gronp. Th
Structure of branched poly-α-amino acids in dimethylformamide. II. Viscosity, sedimentation, and diffusion
✍ Scribed by N. Eliezer; A. Silberberg
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1967
- Tongue
- English
- Weight
- 791 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
The intrinsic viscosity, sedimentation and diffusion of a series of branched, multichain poly-a-amino acids having a poly(b1ysine) backbone and poly( 7-benzyl bglutamate) and poly(j3-benzyl baspartate) side chains was studied at room temperature in dimethylformamide. The molecules were found to beextremely compact structures in which the molecular backbone is either lying along the major axis in a slightly twisted configuration (the longer the side chain the smaller the twist) or is coiled up in the form of a disk with backbone and side chains coplanar. Heat treatment (to 70°C.) introduces only small changes in the hydrodynamic parameters showing that the heat-labile aggregates detected by light scattering are reversibly broken up during the hydrodynamic measurements. The above structural information concerns the initial metastable conformation of the molecules which is irreversibly destroyed by heat treatment.
📜 SIMILAR VOLUMES
Nine samples of poly-ybeneyl-kglutamate (PBLG), ranging in aw from 19,000 to 410,000, were examined viscometrically and by ultracentrifugation with dimethylformamide (DMF) at 25°C. as helicogenic solvent. The data for [v] and SO (limiting sedimentation coefficient) as functions of am were fitted wel