Autodegradation of the extracellular proteases of Brevibacterium linens ATCC 9172

Brevibacterium linens ATCC 9172 produces multiple forms of extracellular pr oteolytic enzymes as shown by polyacrylamide gel electrophoresis (PAGE) and activity staining. Four main bands with strong proteolytic activity, showi ng proteins with molecular weights of 280, 220, 130 and 43 kDa, were distin guished from several bands of lower activity. The formation of smaller enti ties on incubation at 38 degreesC from the isolated main species of proteas es was demonstrated, showing specific sequences in autodegradation. The cel l wall-associated proteases were completely released by incubation of the c ells at 50 degreesC for 2 h and showed a similar isoenzyme pattern. There i s evidence that the multiplicity of proteases is a result of aggregation fr om subunits and of autocatalytic degradation. The enzymes were identified a s serine proteases by specific inhibition. (C) 2001 Elsevier Science Ltd. A ll rights reserved.