Molecular mobility of elastin: effect of molecular architecture.
The thermal and dielectric properties of elastin and two soluble derivatives (kappa-elastin and derived elastin peptides from enzymatic elastolysis) were investigated in the freeze-dried state in a wide temperature range (from -180 to +220 degrees C). The glass transition of these amorphous proteins was studied by differential scanning calorimetry (DSC). The dielectric relaxations of both proteins were followed by thermally stimulated currents (TSC), an isochronal dielectric spectrometry running at variable temperature, analogous to a low-frequency spectroscopy (10(-3)-10(-2) Hz) and by dynamic dielectric spectroscopy (DDS), performed isothermally with the frequency varying from 10(-2) to 3 x 10(6) Hz. The combination of TSC and DDS experiments and the determination of the activation parameters of the relaxation times inform about the molecular mobility of the proteins, both in the glassy state and in the liquid state. Major differences between the relaxation behavior of elastin and its soluble derivatives have been discussed and correlated with the molecular architecture of the proteins.
Samouillan
Valerie
V
Laboratoire de Physique des Polymères, Université Paul Sabatier, 31062 Toulouse Cedex 4, France. vsamou@cict.fr
Dandurand
Jany
J
Lacabanne
Colette
C
Hornebeck
William
W
D002152:Calorimetry, Differential Scanning; D004549:Elastin / Q000737:chemistry*; D005612:Freeze Drying; D019563:Mechanics; D009038:Motion; D010446:Peptide Fragments / Q000737:chemistry; D013057:Spectrum Analysis; D013696:Temperature
D010446:Peptide Fragments; D004549:Elastin