Purification and characterization of recombinant nattokinase from Bacillus subtilis
Keywords:Bacillus subtillis, characterization, nattokinase, puriﬁcation, recombinant
Nattokinase, a thrombosis-degradation serin protease, is obtained from Bacillus subtilis Natto. The enzyme has been clinically proven effective and safe in the treatment of thrombotic disease in humans orally. Nattokinase is produced by solid-state fermentation (SSF) of soybean by Bacillus subtilis Natto so yield and quality should be limited. In recent years, there have been initially researches recombinant nattokinase in bacterial systems (Escherichia coli, Bacillus subtilis, Lactobacillus). This study conducted purified recombinant nattokinase from Bacillus subtillis DB104 strain and surveyed some properties of nattokinase. The crude enzyme was precipitated at 70% saturation of (NH4)2SO4. The optimal pH value and temperature were 8.0 and 55oC, respectively and alkaline stability within the range of pH 6.0-10. The molecular weight of Nattokinase was approximately 27.7 kDa. The apparent Vmax and Km values were 0.306 µmol/min/ml and 6.778, respectively. The enzyme was activated with Mg2+, Zn2+, Ca2+ and obviously inhibited by Mn2+ and Hg2+.