对《普通高中化学课程标准》中氨基与亚硝酸法检测蛋白质含量的商榷

Discussion on Determination of Protein Content by Amino Acid and NitrousAcid Method in General High School Chemistry Curriculum Standards

《普通高中化学课程标准》中检测蛋白质含量的方法是利用氨基与亚硝酸的反应,其原理是α-氨基与亚硝酸可定量生成氮气,但蛋白质侧链和辅基中的含氮基团难以进行上述反应或者无氮气生成,因此该法不能用于检测蛋白质的含量,但可用于测定蛋白质的水解度。通过比较各种检测蛋白质含量的方法——凯氏定氮法、紫外吸收法、双缩脲法、BCA法、folin-酚试剂法、考马斯亮蓝结合法,建议高中化学教学中采用双缩脲法。

The method in the General High School Chemistry Curriculum Standards to measure protein concentrations was based on the determination of free amino groups(as in amino acids or proteins)by measuring the volume or pressure of nitrogen gas formed by reaction with nitrous acid,which was not applicable to proteins with the nitrogen-containing group in the side chain and auxiliary group.Therefore,this method could not be used to detect the protein content,but could be used to determine the hydrolysis degree of proteins.By comparing various methods to quantitatively determine protein content,such as the Kjeldahl method,UV absorbance method,biuret method,bicinchoninic acid(BCA)method,folin-phenol reagent method,and Coomassie brilliant blue(CBB)binding method,the authors suggested that the biuret method should be adopted in general high school chemistry teaching.