In vitro starch binding experiments: Study of the proteins related to grain hardness of wheat

Two friabilin components, puroindoline a and GSP-1 were expressed in Escherichia coli. Starch binding properties of the recombinant polypeptides and of friabilin extracted from wheat flour were compared in vitro. The produced proteins as well as native wheat friabilin bound to starch granules prepared from different (soft, hard and durum) wheat cultivars. Starch granules also bound specifically several wheat endosperm proteins other than friabilin