Purification and characterization of 11s globulin from kutaj ( holarrhena antidysenterica )

Globulins are major seed storage proteins which determine the nutritional quality of the seeds. They form the main source of essential amino acids in the human dietary. The seeds of the Kutaj plant are used in the treatment of various diseases and disorders. Transgenic approaches can be applied to rectify or enhance the content of essential amino acids in seed proteins. It necessitates the study and characterization of globulins from various plant families and sources. Herein, we report the Holarrhena antidysenterica globulin (11S globulin) purified from seeds of Indian medicinal plant, Kutaj. Pure HAG protein was obtained by using DEAE anion-exchange followed by size-exclusion chromatography. The protein exists as a hexamer of ~350 kDa. The SDS-PAGE gel in reducing condition showed bands at ~36 kDa (α subunit) and ~22 kDa (β subunit); and non-reducing condition ~58 kDa which suggest the presence of disulphide bond between the α and β subunit. The N-terminal amino acid sequence of the larger subunit is RQPQLNEAQ and shows high sequence homology with already known 11S seed storage globulin. Molisch’s test indicated that it is a glycoprotein. Glycosylation phenomenon in 11S globulin helps in protein transport from ER to the vacuolar bodies. Keywords : Holarrhena antidysenterica ; seed protein; 11S globulin; lectin like protein; Glycosylation