Purification and characterization of an asialofetuin specific lectin from the rhizome of Xanthosoma violaceum Schott

Lectins are proteins or glycoproteins that bind specifically and reversibly to the carbohydrate or glycoconjugates. A new lectin is purified from the rhizome of Xanthosoma violaceum Schott. by successive steps of ammonium sulfate fractionation and affinity chromatography with asialofetuin as ligand. The purified lectin was found to be a homotetramer of approximately 49 kDa with a subunit molecular weight of 12 kDa linked by non-covalent bonds. Characterization of the lectin shows that the hemagglutination activity is inhibited by asialofetuin and D-galacturonic acid. Hemagglutination activity is shown only in rabbit RBC but not in the human RBC of all blood groups. It is a metal ion-independent glycoprotein of 1.87% carbohydrate content, stable upto 40 degrees C and pH from 5.5 to 9. The lectin shows its optimum hemagglutination activity at 0 degrees C-40 degrees C and pH 6 to 8.5. From LC-MS/MS analysis it is confirmed that the purified lectin was not purified and characterized earlier.

Automated summary

A new lectin with hemagglutination activity was purified from the rhizome of Xanthosoma violaceum Schott. The lectin showed different reactions towards human red blood cells of different blood groups. It exhibited optimal hemagglutination activity at specific temperature and pH range, and showed good stability.