흑두로 제조한 청국으로부터 혈전용해력이 우수한 균을 선발하여 동정하였으며, 그를 Bacillus subtilis BB-1로 명명하였다. 이 균은 혈전용해효소 isozyme을 적어도 5개이상 생성하는 균주로 확인되었다. 이 균으로부터 크로모좀을 분리하여 shot gun법으로 혈전용해효소 유전자를 크로닝하였으며, 이 유전자를 BSF-1이라 명명하였다. 이 유전자는 714개의 아미노산을 암호화하고 있으며 기존에 밝혀진 혈전용해효소 유전자와 상동성은 검출되지 않은 새로운 혈전용해효소 유전자였다. 혈전용해효소활성 최적 pH 및 온도는 5.0과 $35^{circ}C$였다. 기질특이성은 적혈구 배지 또는 skim milk, gelatin등에 전혀 분해활성이 없었다. 이는 혈전만을 특이적으로 분해하는 기질특이성을 보였으며, 혈전분해효소로서의 이용가능성이 충분한 것으로 판단된다.
A bacterium producing five fibrinolytic isozymes was isolated from black bean chung kuk. The bacterium was identified as Bacillus subtilis BB-1 by 16s rDNA sequence homology search. A gene out of five fibrinolytic genes in the Bacillus subtilis BB-1 was cloned by shot-gun method. A Cla I DNA fragment of B. subtilis BB-1 chromosome was cloned in to pBluescript II SK(-) and showed the fibrinolytic activity to bacterial cells. The Cla I DNA fragment was sequenced and the sequences did not show homology with gene for protease or fibrinolytic enzyme genes in other organisms. The Cla I DNA fragment was reduced to 2,142 bp by activity-guided PCR cloning method. The optimum pH and temperature of the enzyme were 5.0 and $35^{circ}C$, respectively. Substrate specificity of the fibrinolytic enzyme was detected in skim milk, casein, gelatin and blood agar plates. The activity of the enzyme was not detected with these substrates. Taken together, this enzyme is a new fibrinolytic enzyme and may be used to prevent thrombosis and arteriosclerosis.
