A. Palop et al., INACTIVATION OF ENZYMES WITHIN SPORES OF BACILLUS-MEGATERIUM ATCC-19213 BY HYDROPEROXIDES, Canadian journal of microbiology, 44(5), 1998, pp. 465-470
The organic hydroperoxides t-butyl hydroperoxide, cumene hydroperoxide
, and peracetic acid were found to act similarly to hydrogen peroxide
in causing inactivation of enzymes within intact spores of Bacillus me
gaterium ATCC 19213 concomitant with mortality. Spores treated with le
thal levels of the agents were germinated and permeabilized for enzyme
assays. The hierarchy of sensitivities among enolase, glucose-6-phosp
hate dehydrogenase (G6Pdh), and pyruvate kinase to inactivation varied
somewhat with the specific hydroperoxide used, possibly because of di
fferences in the types of radicals generated. However, each agent inac
tivated each of the enzymes, albeit at different rates. Comparative as
sessments of enzyme inactivation by lethal levels of H2O2 or by moist
heat showed that some enzymes, such as G6Pdh, are highly sensitive to
inactivation, while others, such as ATPases, are much more resistant.
The enzymes G6Pdh and aldolase were highly sensitive to hydroperoxide
inactivation and also to moist heat, while pyruvate kinase was much mo
re sensitive to hydroperoxides than to moist heat. Our overall interpr
etation of the findings is that hydroperoxides and moist heat can prod
uce cumulative damage to sensitive enzymes within spores, which progre
ssively diminishes the capacities of the cells to undergo the outgrowt
h required for return to vegetative life.