PURIFICATION AND CHARACTERIZATION OF LINECIN A, A BACTERIOCIN OF BREVIBACTERIUM-LINENS

Linecin A is produced by Brevibacterium linens ATCC 9175 and kills some strains of B. linens. Maximum extracellular linecin A activity was 8 units/ml at 48 hr of cultivation, but intracellular linecin A activity rapidly increased after 18 hr of cultivation, reaching 160 units/ml at 36 hr. To release intracellular linecin A from cells, mitomycin C was added to a culture of B. linens ATCC 9175 at a final concentration of 0.3 mu-g/ml. The extracellular linecin A activity increased to nearly 15-fold that of normal cultivation. The extracellular linecin A was purified to a homogeneous state on polyacrylamide gel electrophoresis by DEAE-cellulofine, Sephacryl S-500, and Sephacryl S-300 column chromatography. Linecin A consisted of mostly protein and the molecular weight was estimated to be about 95,000 by gel filtration. Linecin A was a thermolabile protein as the activity was completely lost by incubating at 45-degrees-C for 60 min.