## Abstract Molecular motion in solid poly(Lβalanine), Poly(Lβleucine), poly(Lβvaline), and polyglycine has been investigated through measurement of the portion spinβlattice relaxation time at 30 and 60 MHz between 110 and 350Β°K. Rapid random reoriention of siedβchain methyl groups provides the dom
Heat capacities of solid poly(amino acids). I. Polyglycine, poly(L-alanine), and poly(L-valine)
β Scribed by K. A. Roles; Bernhard Wunderlich
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1991
- Tongue
- English
- Weight
- 665 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0006-3525
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β¦ Synopsis
Heat capacities of polyglycine, poly( L-alanine), and poly (L-valine) were analyzed using approximate group vibrations and fitting of the skeletal vibrations to a two-parameter ( 01, O3 ) Tarasov function. New experimental data were measured by differential scanning calorimetry in the temperature range of 230-390 K. Good agreement between our experimental data and the calculated data was observed for all three poly(amino acids). Previous investigations showed agreement between calculation and reported experimental data for only limited low temperature ranges. A t higher temperatures, discrepancies of up to 55% existed between experiment and calculation. The cause of this discrepancy must be assumed to be experimental error. Recommended experimental data are revised on the basis of this investigation. Computed heat capacities are available for the three biopolymers in the solid state from 0 to 1000 K.
π SIMILAR VOLUMES
In this brief note we extend our previous low-temperature specific heat measurements' on the simplest homopolypeptide polyglycine (Gly),, to the high-temperature range of 15@375 K using differential scanning calorimetry. Polyglycine, or poly(C0-CHR-NH) with R = H. is dimorphic in the solid state,' e
The specific heat a t low temperatures depends on long-range order of the solid because only the long-wavelength phonons are involved. We have recently shown that in biopolymers the secondary and tertiary structures can be studied by such an investigation.' To confirm the results found on L-alanine