351 00 Padova, Ilaly synopsis Circular Dichroism measurements have been carried out on poly-L-lysine (PLL) and on random copolymers of lysine and phenylalanine a t various pH values and in the presence of different amounts of NaClOr. The results indicate that either the homopolymer or the copolymers
A potentiometric and CD investigation on the conformational properties of poly (L-p-aminophenylalanine) in aqueous solution
β Scribed by E. Peggion; A. Cosani; M. Palumbo; M. Terbojevich; M. Goodman
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1976
- Tongue
- English
- Weight
- 665 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0006-3525
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β¦ Synopsis
Abstract
The conformational properties of poly(Lβpβaminophenylalanine) have been investigated by potentiometric and circular dichroism (CD) techniques. It has been found that the polymer in the chargeβfree state can assume two ordered conformations, depending upon temperature conditions. At room temperature the polymer assumes the rightβhanded helical form by described Goodman and Peggion.^1^ At temperatures higher than 40Β°C a new ordered conformation has been found, whose slow rate of formation and ir absorption properties are typical of the Ξ²βstructure. The thermodynamic parameters relative to the coilβΞ² transition, determined by potentiometric titration techniques, revealed that the thermodynamic stability of the Ξ²βstructure is mainly due to enthalpic factors. The formation of this structure is unfavored on a kinetic basis.
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