Thermoanalytical characterization of high molecular weight glutenin subunits - Water effect on their glass transition

The thermal behaviour of the high M-r, glutenin subunits (a group of storag e proteins in wheat grains) 1Dx5, 1Bx7, 1Dx2, 1Bx20, 1Dy12, 1Bx6 and 1Dy10, was investigated using Differential Scanning Calorimetry and Thermogravime tric Analysis. Also included in these studies, for comparison, was a M-r 58 000 peptide (5 8 K) derived from the repetitive domain of subunit 1Dx5 and expressed in Es cherichia Coli. The plasticizing effect of water on each protein was invest igated. When submitted to the calorimetric analysis, the high M-r glutenin subunits exhibited a glass transition phenomenon that was affected by the water con tent. As expected, the glass transition temperature decreased as the water content was increased. (C) 2000 Elsevier Science B.V. All rights reserved.