SODIUM DODECYL SULFATE-INDUCED EMERGENCE OF A NONSPECIFIC PROTEOLYTICACTIVITY IN DESTABILASE, ENDO-EPSILON-(GAMMA-GLUTAMYL)-LYSYL-ISOPEPTIDASE

In the presence of SDS, the highly specific enzyme destabilase, endo-e psilon-(gamma-Glu)-Lys-isopeptidase, acquires a pronounced proteolytic activity towards certain proteins. This is accompanied by the disappe arance of the inherent amidolytic activity (L-gamma-Glu-pNA as the sub strate), while the ability to catalyze monomerization of a fragment of stabilized fibrin (D-D-dimer) is retained. Removal of SDS by gel filt ration eliminates the nonspecific proteolytic activity from destabilas e, and its specific activity is recovered completely. Other detergents of different nature exert a weak effect. A tentative mechanism provid ing for the broadening of destabilase specificity in the presence of S DS is discussed.