Characterization of seed storage proteins of urdbean (Vigna mungo)

Abstract

Dehulled and defatted flour of urdbean (Vigna mungo), Var T-9, contained 25% protein with maximum contribution by globulins (63%). Albumins and glutelins contributed 12% and 21% respectively, whereas prolamins were present only in traces (1%). Globulins were further fractionated into legumin and vicilin type proteins which were present in the ratio of 4:1. All the protein fractions were heterogenous in nature as revealed by high performance liquid chromatography. SDS-polyacrylamide gel electrophoresis revealed the total protein sample to contain 21 different components with molecular weights ranging from 8.92 to 117.49kd. Albumins, globulins, prolamins and glutelins resolved into 4, 8, 6 and 13 different sized components of molecular weights ranging from 10.23 to 25.53, 10.84 to 112.72, 10.33 to 51.52 and 8.91 to 112.72kd, respectively. Amino acid analysis of all fractions revealed that glutamic acid was present in maximum concentration followed by aspartic acid and lysine. Just like other pulse proteins, the urdbean proteins were also deficient in sulphur containing amino acids.