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+) → MnIII-MnIII + 2 H2O
H2O2 + MnIII-MnIII → 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.
Kono Y, Fridovich I. Isolation and characterization of the pseudocatalase of Lactobacillus plantarum. J Biol Chem. 1983 May 25;258(10):6015-9. PMID: 6853475
Barynin V.V. , Whittaker M.M. , Antonyuk S.V. , Lamzin V.S. , Harrison P.M. , Artymiuk P.J. , Whittaker J.W. Crystal structure of manganese catalase from Lactobacillus plantarum. Structure 9 725-738 2001 PMID: 11587647.
Chelikani P. , Fita I. , Loewen P.C. Diversity of structures and properties among catalases. Cell. Mol. Life Sci. 61 192-208 2004. PMID: 14745498.