Molecular Mechanisms in Exercise-Induced Cardioprotection

Table 2

Major antioxidants.

	Name	Role	Remarks
Endogenous enzymes	Superoxide dismutase (SOD); (a) mitochondrial; (b) cytoplasmic; (c) extracellular	Dismutase superoxide to H2O2	(a) Contains manganese (MnSOD); (b) Contains copper and zinc (CuZnSOD); (c) Contains copper (CuSOD)
	Catalase	Dismutase H2O2 to H2O	Present in peroxisomes
	Glutathione peroxidase	Removes H2O2 and lipid peroxides	Selenoproteins (contains Se^2+); Primarily in the cytosol also mitochondria
	Vitamin E	Lipid peroxidation, scavenges superoxide, hydroxyl and lipid peroxide	Fat soluble
Nonenzymatic substance	Vitamin C	Scavenges superoxide, hydroxyl radicals and H2O2, contributes to regeneration of vit E. Neutralizes oxidants from stimulated neutrophils	Water soluble
	β-carotene (provitamin A)	Scavenges⋅OH, O2⋅− and peroxy radicals; Prevents oxidation of vitamin A; Binds to transition metals	Water soluble