Production of two different catalase-peroxidases by Deinococcus radophilus

The production of two kinds of catalase-peroxidase, viz. catalase-2 and cat alase-3 of Deinococcus radiophilus varied depending upon growth phases and oxidative stress. A gradual increase in total catalase activity-occurred du ring exponential and stationary phase. Electrophoretic resolution of these catalases in Deinococcal cell extracts revealed the uniform occurrence of c atalase-2 and the appearance of catalase-3 only during the late exponential and stationary phase. A substantial increase in total catalase was observe d in either hydrogen peroxide- or UV-treated cells. Monitoring of D. radiop hilus catalase activity in the oxidative stressed and non-treated cells by gel electrophoresis followed by densitometry revealed the several-fold incr ease in catalase-3, which is above the constant level of catalase-2. The oc currence of catalase-3 and catalase-2 revealed by fractionation of sucrose- shocked cells suggests that catalase-3 is a cytosolic inducible enzyme wher eas catalase-2 is the membrane-associated constitutive enzyme. (C) 2000 Fed eration of European Microbiological Societies. Published by Elsevier Scienc e B.V. All rights reserved.