Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04179 (MnSOD)
 2,777 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently demonstrated that maize mitochondrial MnSODs are encoded by a differentially expressed multigene family. Molecular characterization of the cloned maize MnSod cDNAs shows that all the maize MnSODs encoded by the cloned MnSod have mitochondrial transit peptides and that the matrix-targeting signal was conserved in all the MnSOD precursor proteins, suggesting that all the maize MnSODs are associated with mitochondria in vivo. In an attempt to clarify the submitochondrial localization of each individual maize MnSOD, each of the maize MnSod cDNAs was introduced into the MnSOD-deficient yeast cells. The functional role and submitochondrial location of each individual MnSOD were examined in the transformed yeast cells. Herein, we demonstrate that all the maize MnSODs can functionally complement the MnSOD deficiency and rescue the transformed yeast cells from oxidative stress induced by paraquat. Biochemical analyses indicate that all of the maize MnSODs are expressed and targeted into the mitochondrial matrix of transformed yeast cells.
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PMID:The maize mitochondrial MnSODS encoded by multiple genes are localized in the mitochondrial matrix of transformed yeast cells. 774

The enzyme superoxide dismutase (SOD), which catalyzes the dismutation of the superoxide radical, is present in the cytosol and mitochondria of all oxygen-respiring eukaryotes. The cytosolic form contains copper and zinc (CuZnSOD), whereas the mitochondrial form contains manganese (MnSOD). The latter protein is synthesized in the cytosol as a MnSOD precursor, containing an N-terminal mitochondrial-targeting sequence. CuZnSOD is sensitive toward cyanide (CN) and hydrogen peroxide (H2O2), but MnSOD is not. Assays for SOD activity in cytosol from the hepatopancreas of the blue crab, Callinectes sapidus, showed the presence of a CN/H2O2-insensitive form of SOD. No CN/H2O2-sensitive CuZnSOD was found. This unexpected phenomenon was shown to occur in all decapod crustacea (crabs, lobsters, shrimp) examined. The cytosolic and mitochondrial SODs of C. sapidus were purified by means of ion-exchange, size-exclusion, and reverse-phase HPLC. The cytosolic SOD is a homodimeric protein, which exists in a monomer-dimer equilibrium (24 kDa left and right arrow 48 kDa). The protein contains approximately 1 Mn per subunit. No copper or zinc is present. Amino acid sequence analysis identified the novel cytosolic SOD as a MnSOD precursor with an abnormal mitochondrial-targeting sequence. The mitochondrial SOD of C. sapidus is similar to the MnSOD found in other eukaryotes. N-Terminal amino sequences of mitochondrial and cytosolic blue crab MnSOD differ in several positions. The MnSODs are thus encoded for by two different genes. The paradigm that all eukaryotes contain intracellular CuZnSOD and that MnSOD occurs exclusively in the mitochondria appears not to apply to a large group of marine arthropods.
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PMID:The paradigm that all oxygen-respiring eukaryotes have cytosolic CuZn-superoxide dismutase and that Mn-superoxide dismutase is localized to the mitochondria does not apply to a large group of marine arthropods. 934 Dec 31