A primary study on nattokinase of bacterium Bacillus sp. isolated from nem chua

Abstract

Nattokinase has been attracted many interest of scientists as this enzyme prevents blood clots in human. Nattokinase, a serine protease, has an ability to degrade blood clots. Many drugs have been used to treat the diseases, caused by blood clots. Among these drugs, nattokinase has been shown as the potential one as its ability for degrading blood clots is 4 times more than that of plasmin. In our study, nattokinase of a bacterium isolated from „nem chua“ was primarily purified by using Hitrap Q column. In addition, the effects of pH, temperature and of some metal ions were also studied here. The enzyme was quite thermostable: after treating at 95oC in 90 minutes the enzyme activity remained 75%. At pH 9 the enzyme activity was maximal. The effects of some metal ions on enzyme activity, in particular, were: the enzyme activity was not affected by ion K+, Na+ in general; the activity was partly inhibited by ion Ni2+, Co2+, Mn2+, Ca2+, Zn2+, Ag+, Fe2+, Cu 2+ (at the concentration of 0.005 M and 0.01 M, except ion Cu 2+ as the activity was completely inhibited by this ion at the concentration of 0.01 M; 0.005 M and 0.001 M); the enzyme activity was activated by ion Mg2+ (the activity was increased around 14%). Nattokinase of a bacterium isolated from „nem chua“ was primarily purified by using Hitrap Q column and 2 protein peaks were obtained; among these peaks, the second pick was with nattokinase activity. After performing electrophoresis of the second peak on the gel with casein at least 6 different protease bands were observed.