ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The reversible helix-to-random coil conformational change which occurs in solvated poly-∊-carbobenzosy-L-lysine, a synthetic polypeptide, has been studied. The course of this cooperative transition, which in many ways resembles a first-order phase transition, was followed both by measuring changes in optical rotation as a function of temperature, and calorimetrically by determining the heat capacity of the solution through the transition region. From the latter measurements, the enthalpy of transition was calculated. From the results it has been shown directly, for the first time, that in a statistical thermodynamical sense, the transition in this system is significantly more cooperative than that undergone by poly-γ-benzyl-L-glutamate, a closely analogous polypeptide. Thus a previously held concept that the degree of cooperation might be quantitatively similar for a wide range of such systems has been shown, for at least one important example, not to be tenable.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360030302
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