Catalase manganese-containing

Marklund, S.L., Westman, N.G., Lundgren, E. and Roos, G. (1982). Copper and zincsuperoxide dismutase, manganese-containing superoxide dismutase, catalase, and glutathione peroxidase in normal and neoplastic human cell lines and normal human tissues. Cancer Res. 42, 1955-1961. 

Subsequently, a manganese-containing catalase has been isolated from the aerobic bacterium Thermoleophilum album (162). The enzyme is 141 kDa and is composed of four subunits of 34 kDa. There were 1.4 + 0.4 atoms of manganese present per subunit. The enzyme could be inhibited by NH2OH but only weakly inhibited by cyanide or azide. The enzyme was colorless at concentrations of 0.7 mg/ml. 

The effect of ischemia-reperfusion injury on activity, protein and m-RNA levels of proteins is also studied. For example, the enzymes that are involved in free radical detoxication (catalase, copper-zinc and manganese containing superoxide dismutase and glutatione peroxidase) were studied in rat kidney [101]. This study... 

There are several different types of catalase. Most animal cells have a form that has four haem molecules embedded in its core. In contrast, some microbes have a different sort of catalase, which contains manganese instead of haem at its core. Despite their different structures, both enzymes are equally fast, and are correctly called catalase, in the sense that they work in the same way — they both catalyse the reaction of two molecules of hydrogen peroxide with each other to form oxygen and water ... 

Human cells have a manganese-containing SOD (Mn-SOD) in the mitochondria, whereas the copper- and zinc-containing SOD (Cu,Zn-SOD) is primarily present in the cytosol [39]. Two enzyme systems exist to catalyze the breakdown of H202. Firstly, the enzyme catalase, which is located in the peroxisomes, converts H202 into H20 and 02 (Eq. 2) [35]. 

The kinetics of formation of the intermediate complex between catalase and HgOa have been re-examined, and reports of pulse radiolysis experiments with superoxide dismutase and its manganese-containing form have appeared. Bovine superoxide dismutase is known to contain two Cu and two Zn atoms per molecule and it has been shown that the copper site, which is directly involved in the catalytic activity, comprises three nitrogens and a water molecule bound to the metal in a field with less than axial symmetry. Less is known of the zinc site but it has recently been shown, by e.p.r. spectroscopy with the cobalt-copper form of the enzyme, that the... 

Bacterial SODs typically contain either nonheme iron (FeSODs) or manganese (MnSODs) at their active sites, although bacterial copper/zinc and nickel SODs are also known (Imlay and Imlay 1996 Chung et al. 1999). Catalases are usually heme-containing enzymes that catalyze disproportionation of hydrogen peroxide to water and molecular oxygen (Eq. 10.2) (Zamocky and Koller 1999 Loewen et al. 2000). 

Catalases catalyze the conversion of hydrogen peroxide to dioxygen and water. Two families of catalases are known, one having a heme cofactor and the second a structurally distinct family, found in thermophilic and lactic acid bacteria. The manganese enzymes contain a binuclear active site and the functional form of the enzyme cycles between the (Mn )2 and the (Mn )2 oxidation states. When isolated, the enzyme is in a mixture of oxidation states including the Mn /Mn superoxidized state and this form of the enzyme has been extensively studied using XAS, UV-visible, EPR, and ESEEM spectroscopies. Multifrequency EPR and microwave polarization studies of the (Mn )2 catalytically active enzyme from L. plantarum have also been reported. ... 

Crystal structures of manganese catalases (in the (111)2 oxidation state) from Lactobacillus plantarum,its azide-inhibited complex, " and from Thermus thermophilus have been determined. There are differences between the structures that may reflect distinct biological functions for the two enzymes, the L. plantarum enzyme functions only as a catalase, while the T. thermo-philus enzyme may function as a catalase/peroxidase. The active sites are conserved in the two enzymes and are shown schematically in Figure 32. Each subunit contains an Mu2 active site,... 

Manganese is an element that is essential for life. It is present at the active site of many en2ymes [4, 5]. Those en2ymes in which the metal center is involved in a redox process are manganese catalase [101], peroxidase [102], and SOD [103]. In addition, a cluster containing four Mn and one Ca atoms in the water-oxidizing center (WOC) of PSII is the site at which dioxygen is produced photosynthetically on Earth [3,104]. 

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