Superoxide dismutase (SOD)

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Superoxide dismutase (SOD) is an enzyme found in all living cells that helps protect the body against potentially harmful oxygen molecules, making it an important antioxidant. Thus, it helps prevent an individual’s cells from being damaged by highly unstable atoms with unpaired electrons, protecting against tissue damage, oxidative stress, and diseases are associated with oxidative stress.

There are three forms of superoxide dismutase in humans that are located in the cytoplasm of the cell (SOD1), the mitochondria (SOD2), and in the extracellular region (SOD3). Studies have found that mice lacking SOD1 developed various diseases that included hepatocellular carcinoma, a cancer of the liver. These mice experienced accelerated age-related muscle mass loss, cataract, and a shorter lifespan.

Other studies have found that mutations in SOD1 are responsible for various pathologies. A case in point would be the disease amyotrophic lateral sclerosis (ALS), a fatal motor neuron disease that causes an individual to experience weakness, muscle atrophy, muscle twitching, and other complication. Simultaneously, elevated level of CuZn-superoxide dismutase has also been found to be dangerous. Overexpression has been found to be associated with patients who have Down’s syndrome.

As for SOD2, studies have found that mice lacking SOD2 experienced high oxidative stress and died soon after birth. SOD2 is also important because it is the first enzyme to scavenge free radicals produced by oxidative phosphorylation, a natural metabolic pathway that generates cellular energy. Thus, this enzyme is vital for preventing mitochondrial enzymes from being inactivated by superoxides. By contrast, mice that did not have SOD3 were found to be more sensitive to hyperoxic injury where there was an excess of oxygen present.


References:

Human mitochondrial manganese superoxide dismutase polymorphic variant Ile58Thr reduces activity by destabilizing the tetrameric interface

Structures of the G85R Variant of SOD1 in Familial Amyotrophic Lateral Sclerosis

The structure of human extracellular copper-zinc superoxide dismutase at 1.7 A resolution: insights into heparin and collagen binding

Superoxide Radical and Iron Modulate Aconitase Activity in Mammalian Cells

Dilated cardiomyopathy and neonatal lethality in mutant mice lacking manganese superoxide dismutase

CuZnSOD deficiency leads to persistent and widespread oxidative damage and hepatocarcinogenesis later in life

Absence of CuZn superoxide dismutase leads to elevated oxidative stress and acceleration of age-dependent skeletal muscle atroph

Amyotrophic lateral sclerosis and structural defects in Cu,Zn superoxide dismutase

Superoxide dismutase ameliorates TNBS-induced colitis by reducing oxidative stress, adhesion molecule expression, and leukocyte recruitment into the inflamed intestine

Topical superoxide dismutase reduces post-irradiation breast cancer fibrosis

Superoxide dismutase, aging, and degenerative disease

Cu/Zn-superoxide dismutase and glutathione peroxidase during aging


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