Purification and characterization of nattokinase from Bacillus subtilis natto B-12.
Bacillus subtilis natto B-12 was isolated from natto, a traditional fermented soybean food in Japan. A fibrinolytic enzyme (B-12 nattokinase) was purified from the supernatant of B. subtilis natto B-12 culture broth and showed strong fibrinolytic activity. The enzyme was homogenously purified to 56.1-fold, with a recovery of 43.2% of the initial activity. B-12 nattokinase was demonstrated to be homogeneous by SDS-PAGE and was identified as a monomer of 29000 +/- 300 Da in its native state by SDS-PAGE and size exclusion methods. The optimal pH value and temperature were 8.0 and 40 degrees C, respectively. Purified nattokinase showed high thermostability at temperatures from 30 to 50 degrees C and alkaline stability within the range of pH 6.0-9.0. The enzyme activity was activated by Zn(2+) and obviously inhibited by Fe(3+) and Al(3+). This study provides some important information for the effect factors of fibrinolytic activity, the purification methods, and characterization of nattokinase from B. subtilis natto B-12, which enriches the theoretical information of nattokinase for the research and development of nattokinase as a functional additive of food.
College of Food Science, Northeast Agricultural University, Harbin 150030, China.
Cong
C
Wang
Ming
M
Du
Dongmei
D
Zheng
Fandong
F
Kong
Guoren
G
Zu
Yibing
Y
Feng
D001412:Bacillus subtilis / Q000737:chemistry / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D004795:Enzyme Stability; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D013025:Glycine max / Q000382:microbiology*; D013381:Subtilisins / Q000737:chemistry* / Q000302:isolation & purification*
D001426:Bacterial Proteins; D013381:Subtilisins; C053771:nattokinase