蚯蚓提取物中蛋白质含量测定方法的研究

Study on the method for determining the values of proteins of earthworm extract

目的寻找能够精确反映蚯蚓提取物中蛋白质含量的测定方法。方法采用改良Lowry法和考马斯亮蓝染料结合法(Bradford法)测定蚯蚓提取物蛋白质含量;分别使用2法测定标准牛血清白蛋白(BSA)水溶液在碱性蛋白酶水解前后的蛋白质含量。结果改良Lowry法的测定结果明显高于Bradford法。BSA水溶液酶解前,2法测定的蛋白质含量相当;使用改良Lowry法,BSA水溶液酶解前后的蛋白测定值相近;而使用Bradford法测定BSA水溶液蛋白质含量时,酶解后的测定值较酶解前出现大幅下降。结论在测定多肽含量多的供试品中蛋白质含量时,改良Lowry法测定更为精确。蚯蚓提取物中存在大量的多肽成分,所以对其进行蛋白质含量测定时,改良Lowry法能够更加精确、真实地反映蚯蚓提取物的蛋白质含量。

Purpose To select the method for determining the values of proteins content in earthworm extract. Methods Determining the values of protein in earthworm extract and in bovine serum albumin （BSA） solution before and after enzymolysis, by using Lowry＇s modified method and Bradford＇s dye-binding method respectively for comparison of the difference from Lowry＇ s modified and Bradford＇ s dye-binding method. Results The values of proteins content in earthworm extract by Lowry＇s modified method were higher than those by Bradford＇s dye-binding method. Before hydrolysis,the values of protein in BSA by two methods were similar. After hydrolysis, the values determined by Lowry＇s modified method became slight higher. On contrary, the values determined by Bradford＇s dye-binding method became much lower. Conclusion Bradford＇s dye-binding method cannot affect the values of peptide. Therefore the values of BSA after hydrolyisis axe much lower. Lowry＇s modified method is sensitive to proteins and peptides. Lowry＇s modified method is more suitable for the determination the values of protein content in earthworm extract.