Bioproperties of potent nattokinase from Bacillus subtilis YJ1

Fibrinolytic enzyme activity was observed during cultivation of Bacillus subtilis YJ1 in a medium containing 1% skim milk, 1% rice husk, 0.5% NaCl, and 0.25% glucose. It was purified to electrophoretical homogeneity after CM-sepharose FF chromatography. The specific activity and yield were 1791.9 FU/mg and 9.5%, respectively. This purified fibrinolytic enzyme had M of 27.5 kDa, optimal temperature and pH at 50 degrees C and 8.5, respectively. It was stable at pH 6.0-10.0 and 10-40 degrees C and inhibited by Fe(3+), Hg(2+), Cu(2+), Zn(2+), and PMSF. Compared the N terminal of amino acids and full DNA sequence with those in NCBI, it was considered to be a nattokinase.