以大豆分离蛋白为底物,游离氨基酸含量、多肽分布、水解度为指标,氨肽酶ProteAXG为 对照,开展中性蛋白酶和氨肽酶双酶协同水解的研究.在底物质量浓度6 g/dL,中性蛋白酶添加量5 000 U/g,氨肽酶添加量9.75×105U/g,pH 8.5,温度50℃,水解4 h后,水解液中游离氨基酸含量13.6 mg/mL,多肽相对分子质量在1100以下,其中600左右的多肽约占16%,二肽三肽 约占75%,水解度达50.8%.氨肽酶与中性蛋白酶优化后,水解度迭62%.结果表明:该氨肽酶无论单独或与中性蛋白酶组合水解,都能达到较为深度的水解效果.%This manuscript with soybean protein isolate as the substrate to study the optimum enzyme hydrolysis parameters of the combination of the neutral protease and aminopeptidase.with free amino acids, peptide distribution, the hydrolysis degree as indexes and aminopeptidase ProteAXG as the control, the optimum conditions were determined and listed as follows:temperature 50℃, substrate concentration of 6 ％, neutral protease addition ratio E/S=5000U/g, aminopeptidase addition ratio E/S= 9. 75 × l0s U/g, pH 8.5 and 4h. Under the optimum conditions, the results of the hydrolyzate is that: the content of free amino acid in the hydrolyzate is 13.6 mg/mL,which is 1.95 times than that of ProteAXG hydrolysis, the molecular weight of the polypeptide is less than ll00D, which consist of by 16％ of 600D and 75％ of dipeptide and tripeptide. The hydrolysis degree achieved at 50.8％. Under the optimum conditions,the degree of hydrolysis is up to 62％. From the above results, we concluded that aminopeptidase from Bacillus subtilis either alone or in combination with the neutral protease, can hydrolyze the soybean isolated protein in-depth.
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