The Extraction,Isolation,Characteristic And Application Of Protease In Siraitia Grosvenorrii

In this paper the documents of siraitia grosvenori and plant proteinase published in the recent years in China were analyzed by applying the methods of document meterology. By evaluating the documental types ,publishing years ,subject fields and so on, the studies on the siraitia grosvenori and plant proteinase were summarized and the current status and developing direction for later research were also pointed out. A new plant enzyme in siraitia grosvenorii was first discoveried and studied in this paper. During the experiments, the studies on the conditions of extracting enzyme, the characters of purified enzyme and enzyme kinetic parameters ,and application of hydrolyzing soybean isolated proteins were mainly concerned about. Through these methods, we got the data of the enzyme's characters and much useful information about application. These results can provide theoretical foundation for further study and industrial use of this kind of enzyme. During the studies on extraction and isolation ,three kinds of method of extracting by alcohol ,tannin, and ultra filration(UF) were introduced and comparied. And the protease was purified by DEAE Sepharose CL-6B chromatography. At the same time ,the properties of the purified protease were studied. The results showed that the enzyem obtained by ultrafiltration has the best quality and high activity .And a single band was found in the gel of isoelectric focusing with the purified protease .Its specific activity was 3475.9×104U/g,its purification ploidy reached 1.87 fold comparied with the crude enzyem obtained by ultra filration,and the recovery ratio of enzyme activity was 5.94 percent. Its isoelectric point determined by isoelectric focusing were found to be pH8.55. The optimum pH was 7.2 or 10.8,and the optimum temperature was 60oC.It was relatilvely stable at temperature blow 40oC and at pH valus ranging from 7.0 to 8.0 or9.5～10.2.Its Km value for casein was 0.0729mmol/L. The enzyme could be activated by cysteine and EDTA ,and inactivated by HgCl2. The protease can be used for the preparation of soybean peptides through hydrolyzing soybean isolated proteins . The optimun hydrolysis condition of soy protein was set up as follow: 600C, pH9.0,substratum concentration 5.0%, proportion of enzyme to substratum 5.0%, hydrolysis time 1h.The mixed peptides of dienzyme hydrolysis had comparatively lighter bitterness and tasted well.