TY - JOUR AB - The course of the reversible helix formation of poly(y-benzyl L-glutamate) (PBG) dissolved in a mixture of dichloroacetic acid (DCA) and 1,2-dichloroethane (EDC) was followed by measuring the heat capacity and the optical rotation of the system through the transition region. The results of these measurements indicate that the transition enthalpy H the transition temperature Tc, and the Zimm-Bragg parameter depend considerably on the PBG concentration as well as on the composition of the solvent. For the standard state of infinite dilution, however, a linear extrapolation of the measured H if values results in a standard value H = 950 cal./mole, independent of the solvent composition. The results of the calorimetric measurements are discussed in relationship to changes in optical rotation. Some peculiarities in the measured thermodynamic and optical properties in solutions with relatively high content of dichloroacetic acid are reported. DA - 1967 DO - 10.1002/bip.1967.360050706 KW - Biophysics KW - Biochemistry KW - Molecular biology LA - eng IS - 7 M2 - 649 PY - 1967 SN - 0006-3525 SP - 649-662 T2 - Biopolymers TI - Experimental thermodynamics of the helix-random coil transition. I. Influence of polymer concentration and solvent composition in the PBG-DCA-EDC system UR - https://nbn-resolving.org/urn:nbn:de:0070-pub-17743550 Y2 - 2024-11-21T21:26:31 ER -