RESPONSE DYNAMICS OF 26-KDA, 34-KDA, 39-KDA, 54-KDA, AND 80-KDA PROTEASES IN INDUCED CULTURES OF RECOMBINANT ESCHERICHIA-COLI

Several researchers have demonstrated that the presence of a heterolog ous protein in recombinant Escherichia coli elicits a response similar to the heat-shock response, which includes enhanced protease expressi on. The present work detects, quantifies, and characterizes intracellu lar protease activity in E. coli that are ''shocked'' by the induction of a recombinant protein, CAT, which is an endogenous protein in some E. coli strains. A novel, sodium dodecyl sulfate gelatin polyacrylami de gel electrophoresis (SDS-GPAGE) method is used to detect, quantify, and characterize the presence of these proteases. A hypothesis is pro posed which links the amplified protease activity to a temporary deple tion of specific amino acid pools, and a stringent-like stress respons e. (C) 1993 John Wiley & Sons, Inc.