摘要
方法:用琥珀酸酐法活化的聚乙二醇对菠萝蛋白酶进行化学修饰,得到菠萝蛋白酶的修饰酶,对比研究三种菠萝蛋白酶:修饰酶、混合酶、天然酶的热稳定性及酸碱稳定性,考察金属离子对三种菠萝蛋白酶的影响。结果:当在55℃水浴保温100min后天然酶活力只保留20%,混合酶活力保留37%,修饰酶活力保留58%;在pH3.0-4.5及pH6.0-7.0的条件下,修饰酶活力高于天然酶活力。当Ca2+的浓度达到0.05mg/mL时,修饰酶的活力高达257.66%;当Mg2+的浓度达到0.035mg/mL时,修饰酶的活力高达147.25%。一价离子Na+对三种菠萝蛋白酶无明显影响。结论:修饰的菠萝蛋白酶对温度和pH值的稳定性均比天然酶有很大程度的提高。混合酶的活力介于天然酶和修饰酶之间说明聚乙二醇对菠萝蛋白酶有一定的保护作用。二价离子Ca2+、Mg2+对三种菠萝蛋白酶活力均有不同程度的激活作用。
Methods： The medified bmlain was obtained by modification with succinic anhydride- activated Polyethylene, the stabihty of modified brolain against temperature and pH and the influence of metal ions on the activity of modified brolain were compared with natural brolain and binlain - PEG mixture. Result： when kept in the water in 55℃ after 100min, the remained activities of natural Brolain and mixed Brolain were respectively 20% and 37%, while the remained activity of modified Bmlain was 58%. When under the conditions of pH3.0 - 4.5 and pH6.0 - 7.0, the activity of modified Bmlain was higher than that of the natural Brolain. When the concentration of Ca^2＋ was 0.05mg/mL, the activity of modified Brelain reached to 257.66% ; when the concentration of Mg2. was 0. 035mg/mL, the activity of the nrxtified Bmlain reached to 147.25%. Na^＋ had hardly any influence on the activity of the three kinds of Brelain. Conclusions： the stability of modified Brolain had increased greatly compared with natural Brolain. The activity of mixed Brolain was between the activities of natural Brolain and modified Brolain, which indicated that PEG had some protective effect on Brolain. Ca^2＋ , Mg^2＋ could increase the activity of the modified Brolain.
出处
《生物技术》
CAS
CSCD
2006年第1期35-38,共4页
Biotechnology
基金
全国教育科学"十五"规划教育部重点课题(DIA030165)
关键词
菠萝蛋白酶
聚乙二醇
琥珀酸酐
化学修饰
brolain
polyethylene glycol
succinic anhydride
Chemical modification
