The ratio of entropy to enthalpy for thermal transitions in biological cells, tissues and materials, and its implications for biology

S. Jacques

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The process of irreversible thermal denaturation of macromolecules involves cooperative bond breakage. Many bonds must break at the same time to allow denaturation. Hence, molecules are stabilized against thermal damage. However, these multiple bonds enforce a structural order on the macromolecule. A review of the literature on the entropy AS (J/(mole K)) and enthalpy ΔH (J/mole) of various endpoints of irreversible thermal denaturation (eg., whitening, contraction, loss of birefringence, necrosis, onset of heat shock proteins) indicate that the ratio ΔS/ΔH is constant at a value of 31.47×10-4 K-1, or 1/Tcrit where T crit ≈ 44.6°C. The free energy of denaturation is ΔG = ΔH - TΔS. At temperatures below Tcrit, more cooperative bonds yield more stability because AH dominates over TΔS, but at temperatures above Tcrit more bonds yield less stable structure because TΔS dominates over ΔH. Only one free parameter describes the kinetics of irreversible denaturation of macromolecules involving simultaneous breakage of multiple cooperative bonds, the ΔH of the transition.

Original languageEnglish (US)
Title of host publicationOptical Interactions with Tissue and Cells XVIII
DOIs
StatePublished - Apr 30 2007
EventOptical Interactions with Tissue and Cells XVIII - San Jose, CA, United States
Duration: Jan 22 2007Jan 24 2007

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume6435
ISSN (Print)1605-7422

Other

OtherOptical Interactions with Tissue and Cells XVIII
CountryUnited States
CitySan Jose, CA
Period1/22/071/24/07

Keywords

  • Coagulation
  • Denaturation
  • Enthalpy
  • Entropy
  • Thermal damage

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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    Jacques, S. (2007). The ratio of entropy to enthalpy for thermal transitions in biological cells, tissues and materials, and its implications for biology. In Optical Interactions with Tissue and Cells XVIII [643502] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 6435). https://doi.org/10.1117/12.715189