Role of cytochrome P-450 in the stimulation of microsomal production of reactive oxygen species by ferritin

These results indicate that P-450, and to a lesser extent, cytochrome b5, play a role in the ferritin-dependent increase in formaion of reactive oxygen species with either NADPH or NADH, most likely reflecting the requirement of these enzymes for microsomal production of superoxide anion

S Puntarulo

2002

Scholarcy highlights

  • Microsomes can remove iron from ferritin by a superoxide-dependent reaction
  • Experiments were carried out to evaluate the role of cytochrome P-450 in the release of iron from ferritin, and whether induction of certain P-450 isoforms alters ferritin-dependent reactive oxygen radical production
  • In the absence of ferritin, formation of reactive oxygen species was higher in microsomes from the treated rats compared to saline controls when results were expressed on a per mg protein basis but not per nmol P-450, suggesting that the increased content of total P-450 rather than the population of isoforms was responsible for ┬Ěh, increase
  • Ferritin increased production of reactive oxygen species with all the microsomal preparations; the increase by ferritin was completely prevented by superoxide dismutase
  • The net increase by ferritin was higher in microsomes from the treated rats compared to saline controls, but this, again, largely reflected the increased content, rather than the type of isoforms of P-450 present
  • Anti-cytochrome b5 IgG produced partial inhibition of the ferritin-stimulation. These results indicate that P-450, and to a lesser extent, cytochrome b5, play a role in the ferritin-dependent increase in formaion of reactive oxygen species with either NADPH or NADH, most likely reflecting the requirement of these enzymes for microsomal production of superoxide anion

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