Biochemical characterization of HMW glutenins in wheat varieties differing in chapati characteristics

Five wheat (Triticum aestivum) varieties differing in their chapati characteristics (C-306, K 68, HD 2745 and HD 2735 - good, Sonalika - Poor) were selected for HMW glutenin characterization. SDS-PAGE of HMW glutenins revealed that polypeptides of MW's 112 kD and 83 kD corresponding to HMW subunits 5 and 10 may be responsible for good chapati characteristics. On reduction and alkylation with urea and acrylonitrile, HMW glutenins gave a very clear distinction between good and poor chapati quality wheat varieties. A 98 kD polypeptide was observed only in good wheat varieties. Peptide mapping of HMW glutenins was carried out using chymotrypsin, trypsin and pepsin enzymes. Chymotrypsin digest showed the presence of 68 and 22 kD polypeptide, trypsin digests also showed the presence of 22 kD and peptic digest showed presence of a 45 kD polypeptide in the good chapati quality wheat varieties.