Abstract: Sodium acetylide was used as carrier and glutaraldehyde was used as cross-linking agent for immobilization of trypsion. The immobilized conditions of trypsin and stability of immobilized trypsin as well as its application in hydrolyzing peanut protein were studied. The results showed that the optimal conditions for immobilizing trypsin are sodium acetylide concentration 3%,quantity of trypsin 4%,glutaraldehyde concentration 3% and CaCl2 concentration 0.2 mol/L. Under these conditions,the recovery rate of trypsin activity is 50.34%. The optimal conditions for hydrolyzing peanut protein are ratio of solid to liquid(W/V) 1:20,pH 7.5,temperature 60 ℃ and quantity of immobilized trypsin 5%. Under these conditions,the highest amount of amino nitrogen is 1.57 mg/ml. After being used for 7 times repeatedly,more than 50% activity of immobilized trypsin remains.

Key words: immobilization, trypsin, sodium acetylide, peanut protein, polypeptide