Identification and purification of the 69-kDa intracellular protease involved in the proteolytic processing of the crystal delta-endotoxin of Bacillus thuringiensis subsp tenebrionis

The dynamics of appearance of intracellular proteases in relation to the sy nthesis of crystal delta-endotoxin was studied to identify the native intra cellular protease(s) involved in the proteolytic processing of the 73-kDa p rotoxin of Bacillus thuringiensis subsp. tenebrionis. In vitro proteolytic activation of the 73-kDa protoxin indicated the possible role of 69-kDa pro tease in the proteolytic processing of 73-kDa protoxin. The purified 69-kDa protease was able to cause the proteolytic activation of the 73-kDa protox in to 68-kDa toxin and this conversion was inhibited by ethylenediamine tet raacetic acid and 1,10-phenanthroline. (C) 2000 Federation of European Micr obiological Societies. Published by Elsevier Science B.V. All rights reserv ed.