摘要
人工底物偶氮酪蛋白(azocasein)在酶的作用下释放发色团,通过分光光度法可以定量嗜冷菌蛋白酶活性。经波长扫描,确定发色物质最大吸收波长为345nm。通过单因素试验,表明试验的最佳参数为:底物与酶反应时间2h,TCA质量分数为12%,TCA终止反应后溶液静止时间30min;该方法在一定浓度范围内线形关系良好(R2=0.9913),样本标准差为8.3×10-4～1.4×10-3,变异系数为0.21%～0.54%,检测限为1.33U/mL;通过对UHT中嗜冷菌蛋白酶活性测定,表明酶活性随温度升高、培养时间延长而增加。
An artificial substrate （azocasein）was used to quantify the proteinase activity from psychrotro phic bacteria through the release of achromogenic product that was measured spectrophotometrically.The highest absorbancy of achromogenic was obtained at 345nm. Through the single factor experiments, the result indicated the optimum parameter were： trichloracetic acid concentration 12%, reaction time between enzyme and substrate 2h, still time 30rain. The method have optimum linear relationship（R2=0.9913）.The precision, measured as coefficient of variation and standard deviation, was 0.21%-0.54% and 8.3×10^-3-1.4×10^-4 respectively. The proteinase activity of psychrotrophic bacteria in UHT milk increased with temperature and time.
出处
《中国乳品工业》
CAS
北大核心
2007年第7期13-16,共4页
China Dairy Industry
基金
国家科研院所社会公益项目(2002005DIA4G035-7)。
关键词
偶氮酪蛋白
嗜冷菌
蛋白酶
azocasein
psychrotrophic bacteria
proteinase
