The heat evolved as a result of irreversible chemical changes that occur on heating 2, 5.6, 15, 25, and 50 wt % water containing wheat gluten has been measured by differential scanning calorimetry. Further, the effects of the removal of water vapors on evaporation of the gluten’s moisture on its polymerization have been investigated. The amount of moisture removed during heating and the heat of the reaction were measured and correlated with the extent of reaction. When the moisture and gases produced on heating gluten were prevented from escaping partially, the total heat evolved decreased, and the reaction exotherm shifted to a higher temperature. These observations have been interpreted in terms of a chemical equilibrium that is attained within the short duration allowed by the heating rate. By varying the amount of water and the time allowed for its diffusion at both ambient temperature and 253 K, it is shown that the thermal effects observed are a consequence of two processes : the vaporization of water, which is endothermic, and the condensation reaction, which is exothermic. The kinetics of this reaction depends upon the amount of water present, which plasticizes the proteins. Increase in the molecular mobility due to the presence of water thus allows further bond formation by chemical reactions, but after the bond has formed, the mobility decreases and some of the water escapes by vaporization because of the exothermic nature of the reactions, thus preventing further reaction. This negative feedback between the physical process of plasticization by water and the chemical process of polymerization thus prevents the reaction from reaching completion. The ultimately formed dry wheat gluten undergoes a glass-softening transition at 436 +/- 2 K. The shape of this endotherm, and so the implicit molecular dynamics, depend upon the thermal treatment conditions of the gluten, but not its T-g onset. It has a broader distribution after reacting in excess water kept at 373 K than when it was degraded and charred by heating to 523 K. This distribution of relaxation times and other characteristics of its heat capacity relaxation are similar to those of synthetic polymers. Wheat gluten seems to be the only material for which a T-g endotherm becomes observable in an experiment done to measure the reaction kinetics.