Purification and characterisation of gelonin from seeds of Gelonium multiflorum

Gelonin, a ribosome-inactivating protein has been isolated from the seeds o f Gelonium multifluorum of Euphorbiaceae family by two methods and the resu lts are compared. In method-I conventional aqueous extraction, cation-excha nge and gel-filtration chromatography has been used. In method-II S-Sepharo se fast flow gel has been used to purify the proteins from the seed extract , followed by ammonium sulfate fractionation, cation-exchange and gel-filtr ation chromatography. Extensive physico-chemical and immunological characte rizations show that molecular weight of gelonin as determined by gel-filtra tion chromatography and SDS-PAGE is similar to 30 kDa. The non-proteinous m aterial which binds to CMC-gel in association with gelonin in method-I is s ubstantially removed when gelonin is purified by method-II. Cation exchange , G-100 chromatography, RP-HPLC and SDS-PAGE show that method-II yields 50% more purified gelonin when compared to the yield by method-I. The immunore activity of gelonin obtained by methods I and II vary from 22-26% and 50-66 % respectively and the ribosome-inactivating property vary from 46-56% and 70-87% respectively.