Objective To optimize the extraction technology of ginger protease by citric acid precipitation, and determine the optimal reaction conditions of enzymatic reaction.MethodsCitric acid precipitation method was used to extract ginger protease from ginger juice. The enzyme activities after adding different concentrations of citric acid were compared. The specific activities of the enzyme were assayed to determine the optimum conditions for enzymatic reaction in different conditions of buffer pH, substrate concentrations and temperatures.ResultsThe highest enzyme activity was 353.153 U when the citric acid concentration was 20 mmol/L. The optimal enzymatic reaction conditions were as follows: concentration of substrate was 1%, reaction temperature was 60℃ , and the pH of buffer was 5. ConclusionThe citric acid precipitation method can extract ginger protease simply and efficiently, and the activity of ginger protease can be rapidly detected by means of the condition optimization of the ginger protease enzymatic reaction .%目的：对柠檬酸沉淀法提取生姜蛋白酶的工艺进行优化,并确立最佳酶反应条件。方法采用柠檬酸沉淀法提取姜汁中生姜蛋白酶,比较加入不同浓度柠檬酸反应后的酶活力值；在不同 pH 缓冲液、底物浓度和温度条件下测定酶比活力,并确定最佳酶反应条件。结果柠檬酸浓度为20 mmol/L时,酶活力最高,为353.153 U。最佳酶反应条件如下：反应底物浓度为1%,反应温度60℃,反应pH值为5。结论柠檬酸沉淀法操作简单、提取效率高,通过生姜蛋白酶酶促反应的条件优化,可以实现生姜蛋白酶酶活的快速测定。
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