Biochemical characterization of two high protein rice cultivars from Assam rice collections

Two high protein rice cultivars viz. ARC 10063 and ARC 10075 from traditional Assam Rice Collections were found to contain about 15 – 16.42% crude protein (Nx5.95) on dry weight basis. The cultivars were analyzed for soluble protein, free amino acids, tryptophan, methionine and lysine contents. Total free amino acid content was found to be higher in the cultivars having higher grain protein content. However, among the three individual amino acids, only lysine was found be higher in the high grain protein containing cultivars. SDS-PAGE of grain proteins showed that except one band which was significantly thicker in the high protein cultivars ARC 10063 and ARC 10075, others were similar between high and low protein containing cultivars. ARC 10063 and ARC 10075 also had an additional slow moving globulin band. Moreover, in addition to two additional bands, one glutelin polypeptide was found to be highly expressed in the high protein cultivars.