Protein heat capacity: inconsistencies in the current view of cold denaturation

The present study shows on the basis of the thermodynamic stability criteri on (partial derivative S/partial derivative T)(p) > 0 that partitioning of the entropy of cold-unfolding of a protein into independent positive confor mational and negative hydrational contributions is incorrect. Furthermore i t provides a new microscopic interpretation of protein heat capacity that t akes into account the significant fluctuations in energy and entropy which result from the small size of these macromolecules. (C) 1999 Elsevier Scien ce B.V. All rights reserved.