Bacillus sp. strain DJ-4, which produces extracellular proteases, was screened from Doen-Jang, a traditional Korean fermented food. A fibrinolytic enzyme (subtilisin DJ-4) was purified using commercial chromatographic techniques. The relative molecular mass of the isolated protein was 29 kDa by SDS-PAGE and fibrin zymography assay. The enzyme was characterized as a serine protease by an inhibitor assay on the fibrin zymography gel and by an amidolytic assay using a chromogenic substrate. The enzyme was inhibited by PMSF, but not by EDTA or leupeptin. The first 14 amino acids of the N-terminal sequence were identical to that of subtilisin BPN', but the activity of subtilisin DJ-4 was 2.2 and 4.3 times higher than those of subtilisin BPN' and subtilisin Carlsberg, respectively.

No abstract

No abstract

No abstract

Based on the zymography analysis, Bacillus sp. DJ-4 (screened from Doen-Jang, a Korean traditional fermented food) secretes seven extracellular fibrinolytic enzymes (EFEs; 68, 64, 55, 45, 33, 27, and 13 kDa) in culture broth. These seven EFEs were analyzed by newly applied SDSfibrin zymography combined with gradient polyacrylamide (SDS-FZGP). This improved gel system was used with a 5-20% acrylamide gradient in a fibrin zymogram gel for the separation of proteins with molecular masses from below 10 kDa to over 100 kDa on one gel plate. Using this system, high molecular weight bands (HMWBs) were clearly and sharply resolved. We also examined the relationship between an acrylamide concentration and the enzymatic activity of EFE using densitometric analysis.