The heme oxygenase system and cellular defense mechanisms

摘要: Heme oxygenase isozymes, HO-1, HO-2 and HO-3, are HSP32 protein cognates, with a known function of catalyzing the isomer specific oxidation heme molecule, including that NO synthase. Unknown until recent years was system is central component cellular defense mechanisms; this can be attributed to combination many factors. In biological systems HO activity responsible for production equimolar amounts CO, biliverdin free Fe. The serine/threonine kinase, reductase, catalyzes reduction bilirubin. Bilirubin potent antioxidant CO signal molecule. Although both active isozymes catalyze same reaction, HO-1 may in rather distinct fashion protection against tissue injury. stress responsive cognate rapidly induced by stable radicals as well hypoxia. Supra induction completely protects ischemic kidney pathology. This involves rapid inactivation pro-oxidant denatured hemoproteins converting it bilirubin CO. case severe injury, such compression colocalizes cGMP pro-apoptotic oncogenes. HO-2, which constitutive form, addition maintaining cell homeostasis, inactivates derived radicals. isozyme binds radical at its “heme regulatory motifs” “suicide” inactivated transcript levels. Data shown provide evidence role mechanism radical-mediated damage, consistent forwarded concept have common, distinct, roles mechanisms.