Characterization of a 27 kDa fibrinolytic enzyme from Bacillus amyloliquefaciens CH51 isolated from cheonggukjang.

Bacillus amyloliquefancies CH51 isolated from cheonggukjang, a traditional Korean fermented soy food, has strong fibrinolytic activity and produces several fibrinolytic enzymes. Among four different growth media, tryptic soy broth was the best in terms of supporting cell growth and fibrinolytic activity of this strain. A protein with fibrinolytic activity was partially purified from the culture supernatant by CMSephadex and Phenyl Sepharose column chromatographies. Tandem mass spectrometric analysis showed that this protein is a homolog of AprE from B. subtilis and it was accordingly named AprE51. The optimum pH and temperature for partially purified AprE51 activity were 6.0 and 45 degrees , respectively. A gene encoding AprE51, aprE51, was cloned from B. amyloliquefaciens CH51 genomic DNA. The aprE51 gene was overexpressed in heterologous B. subtilis strains deficient in fibrinolytic activity using an E.colo-Bacillus Shuttle vector, pHY300PLK.