以分离于新疆北部地区部分奶牛场中临床型乳房炎样品中的主要致病菌-链球菌为研究对象,采用硝基酚α-D-吡喃半乳糖苷(pNP--αGal)作为α-半乳糖苷酶反应的底物,进行酶促反应,通过405 nm的波长进行比色并测定其吸光度(OD值)。结果表明:测定α-半乳糖苷酶活性最佳pH值为5.5;所需时间为10 min;反应温度为40℃。α-半乳糖苷酶活力的测定受底物液的pH值、链球菌选择培养基、作用时间等关键因素的影响。

The object of this study was to separate the pathogenic bacteria streptococcus in the north part of Xinjiang from clinical mastitis on dairy farms.Using p-nitrophenol α-D-galactopyranoside(pNP-α-Gal) as α-galactosidase substrate reaction to make enzymatic reaction,which were measured by colorimetric and absorbance(OD) in the wavelength of 405nm.The results showed that α-galactosidase activity in the best pH value was 5.5,the optimal time was 10 min,and reaction temperature was 40℃.The influence factors of α-galactosidase activity determined were the substrate solution pH,Streptococcus selective medium,time and the key factors.