蛋白质含量测定的教学改进

Teaching improvement on the determination of protein content

凯氏定氮法是经典的蛋白质含量测定方法,在科学研究和生产实践中应用广泛。蛋白质折算系数(NPF)是影响该法结果准确性的关键参数,在现行的生物化学教材中多数认为该值近似为6.25,实际上由于原料的化学组成不同,NPF可能与6.25有较大差异。这一点在教学过程中很容易被忽视,使教学内容不准确,甚至影响学生未来的实际应用。教师在课堂中进行教学改进,系统介绍了凯氏定氮法及NPF的研究历史,整理了常见原料的NPF,同时还总结了不同蛋白质测定方法的优缺点和适用条件,并以白菜为例比较了凯氏定氮法和考马斯亮蓝法测试结果的差异。这些内容不仅可以拓宽学生视野,让学生对凯氏定氮法及NPF有更加科学的认识,还是对现有课程教学内容的补充和完善,为今后国内生物化学等相关课程教学改革提供了参考。

Kjeldahl method, as a standard method for quantifying protein, is widely used in scientific research and industrial practice. The nitrogen to protein factor(NPF) is a key parameter that affects the accuracy of the experimental result in this method, which is estimated to be 6.25 in most current Biochemistry textbooks. Indeed, NPFs may not always be 6.25 due to the differences in chemical composition, which is typically ignored in the teaching process and makes the teaching content inaccurate. The authors conducted the teaching innovation and introduced the research history of Kjeldahl method and NPF in class and summarized the NPF values of common raw materials. Besides, the advantages, drawbacks and applicable condition of different protein determination methods were also compared. Finally, a comparative experiment between Kjeldahl and Bradford methods was conducted using cabbage as a representative. This work can not only give a deeper understanding of Kjeldahl method for students but also provide a perfection for existing teaching content, and offers a useful reference for the reform and improvement of Biochemistry courses in the future.