Diagnostic Tools Enzyme Preparation And Stability Of The Study

With the development of genetic engineering and protein engineering, lots of proteins can be got easily. But the proteins are not stable in solution. During diagnoses, we use a lot of enzymes, which are stored in the solution generally.so how to make the protein stabilization in the solution is very important. Homocysteine is relation to 100 diseases, so its assay has been mounting interesting recently.The CBL and CBS are the important diagnostic enzymes during the mensurate of Homocystein. This paper presents investigation in the effect of additives on the stabilization of CBL towards storage in the solution.The cystathionine β lyase gene was cloned from the DNA of Escherichia coli by PCR, then the cloned gene was constructed with plasmid pET-23a(+)&pET-28a(+) and transformed into E. coli BL21(DE3).The two recombinant strains were named as BL21(DE3)(pET-23a(+)) and BL21(DE3)(pET-28a(+)) respectively. Finally, purification by 6 × His/Ni-NTA and CBL is got fruitful. In different concentration and temperature, we study nine additives respectively and find eight of them have shown to increase the stability of trypsin. The effect of PEIs are better than others .Then we choose the PEIs and study the effect of its stabilization in the CBL solution.The studies presented in this paper clearly demonstrate that PEI could effectively improve the shelf life of CBL at temperatures of 4℃ and 37℃. The CBL without PEIs is deactivation in one month, but with PEIs additives, after one month,at 4℃ and 37℃,the maximum activity retain 53.8% and 35.3% respectively.