Effects of wheat bug (Eurygaster maura) proteolytic enzymes on electrophoretic properties of gluten proteins

Hydrolysis of gluten proteins of six bread wheat (Triticum aestivum L.) cultivars damaged by Eurygaster maura was investigated by acid polyacrylamide gel electrophoresis (A-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Electrophoresis results showed that bug proteolytic enzymes clearly affected gliadin and glutenin proteins of damaged wheats. Some new bands of low and high mobility appeared in the A-PAGE electrophoregrams. These new bands and the bands in the original gliadin and glutenin patterns disappeared with increasing incubation times. Especially high molecular weight (HMW) glutenin subunits were most strongly affected by the bug protease, and disappeared at 120 min of incubation (except 'Ankara'). However, some of the low molecular weight (LMW) glutenin subunits were not affected as much as HMW glutenin subunits and were still visible even after the longest incubation time investigated. Electrophoretic patterns of some cultivars with the same level of proteolytic activity were affected differently, indicating an intercultivar variation in susceptibility to hydrolysis by bug proteolytic enzymes.