[Stability of isoenzyme C of the collagenolytic protease from the crab Paralithodes camtschatica]. / Stabil'nost' izofermenta s kollagenoliticheskoi proteazy kraba Paralithodes camtschatica.

The stability of the isozyme C of the collagenolytic protease of the king crab (Paralithodes camtschatica) has been studied. It has been shown that protease C is stable at mild alkaline conditions; marked inactivation is observed only at temperatures above 40 degrees C. Under these conditions the enzyme thermoinactivation is a monomolecular process. CaCl2 and NaCl have no effect on the thermoinactivation process. At pH < 6 the enzyme is rapidly and irreversibly inactivated, presumably due to the autolytic cleavage. At acidic conditions the enzyme is strongly stabilized in the presence of CaCl2, this effect being critically dependent on the salt concentration. A stabilizing effect is also observed by an increase in the protease C concentration. The enzyme is the most labile in strongly alkaline condition; the process its inactivation at pH 11.25 is not dependent on the enzyme concentration. The protease C retains its activity in the presence of detergents but is effectively inhibited by guanidine chloride.