J. Biol. Chem., Vol. 265, Issue 1, 42-46, 01, 1990
Hydrogen peroxide mediates the oxidative inactivation of enzymes following the switch from anaerobic to aerobic metabolism in Klebsiella pneumoniae
M Chevalier, EC Lin and RL Levine
Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892.
Klebsiella pneumoniae utilizes distinct pathways for the anaerobic and
aerobic metabolism of glycerol. During anaerobic growth, glycerol is first
converted to dihydroxyacetone by glycerol dehydrogenase; subsequent
phosphorylation yields dihydroxyacetone phosphate. During aerobic growth,
glycerol is initially phosphorylated to yield glycerol 3-phosphate;
subsequent reduction then gives dihydroxyacetone phosphate. A coordinated
response occurs when anaerobically growing cells are switched to aerobic
conditions. Synthesis of glycerol dehydrogenase is repressed, glycerol
dehydrogenase is inactivated, and the protein is degraded. Ethanol
dehydrogenase and propanediol oxidoreductase are also inactivated when
cells are exposed to oxygen (Johnson, E. A., Levine, R. L., and Lin, E. C.
C. (1985) J. Bacteriol. 164, 479-483). Exposure of anaerobically growing
cells to low concentrations of hydrogen peroxide also inactivated these
three enzymes and led to rapid degradation of glycerol dehydrogenase.
Glycerol dehydrogenase was purified and characterized after in vivo
oxidative modification initiated by hydrogen peroxide. No differences in
molecular weight, amino acid composition, or Km were detected between the
native and oxidatively modified forms, although the modified enzyme had
only 10% of the catalytic activity of the native form. The oxidatively
modified enzyme was very susceptible to degradation by subtilisin while the
native enzyme was resistant. Chloramphenicol prevented the inactivation and
degradation of glycerol dehydrogenase caused by exposure to oxygen but did
not block that caused by hydrogen peroxide. Thus, protein synthesis appears
necessary for in vivo oxidative modification caused by exposure to oxygen
but is not necessary when the process is initiated by exposure to hydrogen
peroxide. The newly synthesized protein(s) presumably catalyzes the
production of hydrogen peroxide which is required for the metal- catalyzed
oxidative modification of susceptible enzymes.