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Superoxide dismutase

Superoxide dismutase
Superoxide dismutase 2 PDB 1VAR.png
Structure of a human Mn superoxide dismutase 2 tetramer.
Identifiers
EC number 1.15.1.1
CAS number 9054-89-1
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Copper/zinc superoxide dismutase
1sdy CuZnSOD dimer ribbon.png
Yeast Cu,Zn superoxide dismutase dimer
Identifiers
Symbol Sod_Cu
Pfam PF00080
InterPro IPR001424
PROSITE PDOC00082
SCOP 1sdy
SUPERFAMILY 1sdy
Iron/manganese superoxide dismutases, alpha-hairpin domain
1n0j H mit MnSOD D1 rib.png
Structure of domain1 (color), human mitochondrial Mn superoxide dismutase
Identifiers
Symbol Sod_Fe_N
Pfam PF00081
InterPro IPR001189
PROSITE PDOC00083
SCOP 1n0j
SUPERFAMILY 1n0j
Iron/manganese superoxide dismutases, C-terminal domain
1n0j H mit MnSOD D2 rib.png
Structure of domain2 (color), human mitochondrial Mn superoxide dismutase
Identifiers
Symbol Sod_Fe_C
Pfam PF02777
InterPro IPR001189
PROSITE PDOC00083
SCOP 1n0j
SUPERFAMILY 1n0j
Nickel superoxide dismutase
94-SuperoxideDismutase-Ni 6mer.png
Structure of Streptomyces Ni superoxide dismutase hexamer
Identifiers
Symbol Sod_Ni
Pfam PF09055
InterPro IPR014123
SCOP 1q0d
SUPERFAMILY 1q0d

Superoxide dismutase (SOD, EC 1.15.1.1) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O2) radical into either ordinary molecular oxygen (O2) or hydrogen peroxide (H2O2). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. Hydrogen peroxide is also damaging and is degraded by other enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen. One exception is Lactobacillus plantarum and related lactobacilli, which use a different mechanism to prevent damage from reactive (O2).

SOD enzymes deal with the superoxide radical by alternately adding or removing an electron from the superoxide molecules it encounters, thus changing the O2 into one of two less damaging species: either molecular oxygen (O2) or hydrogen peroxide (H2O2). This SOD-catalyzed dismutation of superoxide may be written, for Cu,Zn SOD, with the following reactions :

The general form, applicable to all the different metal-coordinated forms of SOD, can be written as follows:

where M = Cu (n=1) ; Mn (n=2) ; Fe (n=2) ; Ni (n=2).

In a series of such reactions, the oxidation state and the charge of the metal cation oscillates between n and n+1: +1 and +2 for Cu, or +2 and +3 for the other metals .


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Wikipedia

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