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Calorimetry of rat tail tendon collagen before and after denaturation: the heat of fusion of its absorbed water
Author(s) -
Haly A. R.,
Snaith J. W.
Publication year - 1971
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360100921
Subject(s) - chemistry , enthalpy of fusion , fusion , denaturation (fissile materials) , tendon , calorimetry , melting point , differential scanning calorimetry , thermodynamics , analytical chemistry (journal) , chromatography , anatomy , nuclear chemistry , organic chemistry , medicine , philosophy , linguistics , physics
The specific heat, of rat tail tendon at various water contents was measured as a function of temperature. The resulting graphs showed peaks arising from the melting, near 50°C, of helical material in the collagen, and from the melting of absorbed water in the range ‐40°C to 0°C. The heat of melting of helical material was 11.7 cal per gram of dry tendon. Determination of the heat and temperature of fusion of the absorbed water allowed resolution of the water into four states in the case of tendon before denaturation, and three states after denaturation. The four states are ( 1 ) water not freezable on cooling to ‐ 70°C, ( 2 ) freezable water with‐both heat and temperature of fusion different from the values for ordinary water, ( 3 ) freezable water with the heat of fusion of ordinary water, but a different temperature of fusion, and ( 4 ) water not distinguished from ordinary water. The fourth state was absent in denatured tendon. The results are discussed in terms of increasing size of clusters of absorbed water molecules.