Mutual synergy between catalase and peroxidase activities of the bifunctional enzyme KatG is facilitated by electron hole-hopping within the enzyme.

ABSTRACT: KatG is a bifunctional, heme-dependent enzyme in the front-line defense of numerous bacterial and fungal pathogens against H₂O₂-induced oxidative damage from host immune responses. Contrary to the expectation that catalase and peroxidase activities should be mutually antagonistic, peroxidatic electron donors (PxEDs) enhance KatG catalase activity. Here, we establish the mechanism of synergistic cooperation between these activities. We show that at low pH values KatG can fully convert H₂O₂ to O₂ and H₂O only if a PxED is present in the reaction mixture. Stopped-flow spectroscopy results indicated rapid initial rates of H₂O₂ disproportionation slowing concomitantly with the accumulation of ferryl-like hem

SUBMITTER: Njuma OJ 

PROVIDER: S-EPMC5682954 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature