Studies On Enzymatic Properties Of Nattokinase And Preparation Of Microcapsules

Nattokinase is a serine protease that produced by the Bacillus subtilis, its main function is to dissolve the thrombus, and also as a new generation of thrombolytic drugs got the corresponding development and research. This paper mainly studies the enzymatic properties of nattokinase and the production process and stability of microcapsules which embedded by sodium alginate.The molecular weight of nattokinase was 28 k Da and the isoelectric point of it was8.58. The enzymatic activity of nattokinase was 62520 U/g determined by fibrin agarose plate method. It was determined at different heating temperature that the higher the temperature, the lower the enzymatic activity of nattokinase. The optimum reaction p H was 6.5, the optimum reaction time was 60 min. When concentrations of sodium chloride was less than 1.35 mol/L, the enzymatic activity of nattokinase played a accelerate role, but with higher than this concentration, nattokinase showed an evident inhibition. It has been also found that magnesium ion, calcium ion had a very little activated effect on enzymatic activity;while zinc, iron and copper ions had the inhibitory effect.The optimal process condition of microcapsule prepared by nattokinase embedded by sodium alginate was as follow, 1.60% of sodium alginate concentration, 0.50%of sodium carboxymethyl cellulose concentration, 0.30% calcium chloride concentration concentration.In the comparison of enzyme properties, it was found that there were differences between embedded and free nattokinase. Even at different temperatures or different p H value, the enzymatic activity of embedded nattokinase was higher than free nattokinase.And when the reaction temperature was 50℃, the relative enzymatic activity of free nattokinase was 51.69%, while the relative enzymatic activity of embedded nattokinase was 71.67%. Under conditions of p H value was 8.5, the enzymatic activity of embedded nattokinase was also higher than free nattokinase. Therefore, enzymatic activity can be protected from the external circumstance through embedding by sodium alginate.Likewise, it was found that in research of mixed polysaccharides embedded by sodiumalginate / CMC had the advantantages of small particle size, regular morphology, high recovery of enzymatic activity and high hardness.