Extraction Of The Catalase From Leaves Of Schisandra Chinensis (Turcz.) Baill And Its Immobilization

Schisandra chinensis?Turcz.?Baill in North Changbai Mountain is a kind of herbaceous plant resource with medicinal and edible functions in China since ancient times.Our early research found that although the fruit has been widely used,it has not brought enough economic value to farmers,resulting in a decrease in recent years.The economic value of Schisandra could be improved if the leaves of Schisandra as waste were used as raw material.In the early study,catalase was present in the cotyledons.Catalase is a kind of food additive with the functions of disinfection,bleaching and protection of nutrition in soft drinks.Therefore,catalase was extracted and purified by using catalase activity as Index.The optimum stability condition was determined,and the kinetic model of enzyme reaction was established.Catalase was immobilized by chitosan.Specific experiments and conclusions are as follows:The optimal conditions for the extraction of catalase from the leaves of Schisandra were studied by using the activity of catalase.Three main factors were selected to optimize by the Box-Behnken response surface method.The best results were as follows:The extraction temperature was 46?and the extraction pH was 7.The catalase was purified by salt precipitation method combined with Sephadex G-75 gel filtration method.The maximum purification multiple reached 9.69 times.The absorption peak of catalase at 240 nm was obtained by ultraviolet absorption spectroscopy.According to SDS-PAGE electrophoresis,the molecular mass of catalase was 68.7 kD.The purity of catalase was 91.037%by HPLC.The effects of pH,thermal stability,organic compounds,organic solvents and metal ions on catalase stability were investigated.The results showed that the temperature of catalase was 25³5?at pH 7.0,and the stability was very well.Oxalic acid,Cu²⁺,Mg²⁺had some activation effect on catalase from the leaves of Schisandra.Methanol,ethanol,isopropanol,tartaric acid,salicylic acid,maltose,glucose,Mn²⁺and Na⁺had some inhibition on catalase from the leaves of Schisandra.The constant K_m value of catalase was determined to be 8.372 mmol/L by the Lineweaver-Burk method.The Half-Life and activation energy of catalase from the leaves of Schisandra were obtained by Km value of deactivation mechanics constant and the relationship between temperature and deactivation mechanics constant.When the temperature of catalase rose to 65?,the half-life of catalase was 1.37 min Catalase activation energy?E was 2.135 X 10³J/mol.