At first, these potentiators were thought to simply inhibit catalases, but recent findings with cyanide suggest that potentiators mostly promote the other side of Fenton’s reaction, recruiting iron from cell depots into stable DNA-iron complexes that, in the presence of elevated H 2O 2, efficiently break duplex DNA, pulverizing the chromosome. Here we review several examples of how cells potentiate H 2O 2 toxicity with other chemicals.
And yet, low concentrations of H 2O 2 are somehow used as an efficient biological weapon. Because of the immediate danger of H 2O 2, all cells have powerful H 2O 2 scavengers, the equally famous catalases, which enable cells to survive thousand-fold higher concentrations of H 2O 2 and, in combination with adequate movement of H 2O 2 across membranes, make the killing H 2O 2 concentrations virtually impractical to generate in vivo. This life-specific reactivity follows distribution of soluble iron, Fe(II) (which combines with H 2O 2 to form the famous Fenton’s reagent), - Fe(II) is concentrated inside cells, but is virtually absent outside them.
Hydrogen peroxide (H 2O 2) is unique among general toxins, because it is stable in abiotic environments at ambient temperature and neutral pH, yet rapidly kills any type of cells by producing highly-reactive hydroxyl radicals.
0 kommentar(er)
