Description

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 + Mn^II-Mn^II(2H⁺)  → Mn^III-Mn^III + 2 H₂O
H₂O₂ + Mn^III-Mn^III  → Mn^II-Mn^II(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.