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Title: A study of some physical properties of collagen
Author: Menashi, Shoshana
ISNI:       0000 0001 3393 5521
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1977
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The stability of collagen has been examined using differential scanning calorimetry and microcalorimetry. Attempts have been made to relate changes in temperature and enthalpy of denaturation to known or predicted changes in conformation. The calorimetric enthalpy of denaturation was an order of magnitude larger than that calculated by the van't Hoff procedure, indicating that collagen denaturation is not a simple two-state transition. This result was interpreted in terms of independently-melting cooperative regions in tropocollagen. Studies on collagen of varying imino acid content showed that the thermostability of both soluble and insoluble collagen increased with increasing imino acid content. however, increased only in the soluble collagen samples and was approximately constant for the insoluble collagen. This was explained by proposing that, in tropocollagen, the pyrrolidine rings encourage structuring of water in their immediate vicinity, while in the fibre these residues might be involved in interchain hydrophobic bonds. The effect of selective reagents on soluble and insoluble collagen indicated that hydrophobic interactions may account for about 25% of the energy released on denaturation of insoluble collagen, while in soluble collagen their contribution is negligible. Isothermal microcalorimetric studies on these same reactions suggest that with denaturing reagents the collagen fibre loses its integrityin two stages, the first involving the rupture of intermolecular bonds, while the second stage involves rupture of intrahelical bonds. Experiments on the aggregation of tropocollagen with ATP and chondroitin-sulphate supported the proposal that electrostatic interactions are involved in this aggregation. Human collagen samples of varying age and with different smoking histories were examined in a scanning calorimeter and a correlation between the thermal features and age and/or smoking was attempted. The results reported in this thesis are discussed in the light of available data on the organisation of collagen molecules at the molecular and fibrillar level.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physical Chemistry