Abstract

• Urease (E.C 3.5.1.5) was isolated and purified from dehusked pigeonpea seeds (Cajanus cajan L.). The purification method involved ammonium sulphate precipitation, Sephacryl S-200 gel filtration and DEAE Sepharose ion-exchange chromatography. The specific activity, the relative purity of the enzyme urease was increased by 398 fold over that of crude extract. The purified urease enzyme was found to have the specific activity of 306.67 μmol min-1mg-1 of protein. The purity of the enzyme was confirmed by non SDS-PAGE as single band. The molecular weight for purified urease was found to be 478 kDa (kilodalton). The immobilization of the purified urease was carried out by gel entrapment technique using sodium alginate. Determination of urea content in dried skate fish before and after removal by pigeonpea urease was carried out by using immobilized urease. After 66 h, 75.94 % of urea was removed from dried skate fish.