HYDROPEROXIDE INACTIVATION OF ENZYMES WITHIN SPORES OF BACILLUS-MEGATERIUM ATCC19213

Hydroperoxide inactivation of the protoplast enzymes enolase, aldolase and glucose-6-phosphate dehydrogenase in intact spores of Bacillus me gaterium ATCC19213 was assessed by first treating the cells with letha l levels of H2O2, then germinating them in the presence of chloramphen icol prior to permeabilization and enzyme assays. Glucose-6-phosphate dehydrogenase proved to be more sensitive to H2O2 than enolase or aldo lase, in agreement with findings for isolated enzymes. Average D value s (time for 90% inactivation) for spores treated with 0.50% H2O2 were 173 min for enolase, 67 min for aldolase and 32 min for glucose-6-phos phate dehydrogenase, compared with a D value of 34 min for spore killi ng. H2O2 killing of spores was found to be conditional in that recover ies of survivors were greater on complex medium than on minimal medium . Overall, it appeared that oxidative inactivation of enzymes may be i mportant for hydroperoxide killing of spores.