Manganese catalase (MnCat)
Manganse catalase is a non haem containing protein. They are sometimes referred to as pseudocatalases, constitute one minor catalase family and have a relatively small subunit size (28 to 36 kDa). They use two manganese ions instead of ferric heme in their active site. MnCat are able to catalyse the following reaction. H2O2 + MnII-MnII(2H+) â†’ MnIII-MnIII + 2 H2O H2O2 + MnIII-MnIII â†’ MnII-MnII(2H+) + O2 The nonheme catalases are not as widespread as the other heme-containing catalases. They have been identified only in bacteria and are poorly represented in Archeaebacteria (only detected in different Pyrobaculum) and Bacteroidetes/Chlorobi (only detected in Bacteroides caccae and Bacteroides capillosus). MnCat encoding sequence is dectected neither in Chlamydiae/Verrucomicrobia nor in Deltaproteobacteria nor in Epsilonproteobacteria.
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