Bacteria catalase

In another method, hydrogen peroxide can be added to the Hquid egg white after it has been heated at 52°C for a holding time of 1 minute (18) to inactivate the natural catalase and to allow the hydrogen peroxide to react against bacteria. Hoi ding time after addition of the hydrogen peroxide is 2.5 min... 

Superoxide is formed (reaction 1) in the red blood cell by the auto-oxidation of hemoglobin to methemo-globin (approximately 3% of hemoglobin in human red blood cells has been calculated to auto-oxidize per day) in other tissues, it is formed by the action of enzymes such as cytochrome P450 reductase and xanthine oxidase. When stimulated by contact with bacteria, neutrophils exhibit a respiratory burst (see below) and produce superoxide in a reaction catalyzed by NADPH oxidase (reaction 2). Superoxide spontaneously dismu-tates to form H2O2 and O2 however, the rate of this same reaction is speeded up tremendously by the action of the enzyme superoxide dismutase (reaction 3). Hydrogen peroxide is subject to a number of fates. The enzyme catalase, present in many types of cells, converts... 

The enzyme is produced by aerobic microbes, which live in the mill waters and in the bio-film located on all wet surfaces. When these bacteria are teased with low concentrations of HP, which is the case in all mills that are using HP, the population will change so that the individuals with the highest catalase activity will have the best opportunities to survive. This adapted population grows and infiltrates the whole circulation water system. 

High bacteria levels (>108 p/ml) of which almost all were catalase positive. 

Later research and full-scale trial have shown that bacteria levels higher than 106 p/ml are dangerous and it is just a matter of time before problems return. If the levels on the other hand are lower than 104 p/ml the process will be stable and it is unlikely that disturbances will occur. (The absolute levels of bacteria may vary due to catalase activity and method of measurement). 

Immuno-histochemical staining of intracellular bacteria in filarial nematodes has been obtained using antibodies against GroELand catalase (Henkle-Duhrsen etal., 1998 Hoerauf etal., 1999) the specificity of these antibodies is unknown, but it is expected to be low because both GroEL and catalase show high level of amino acid conservation throughout the proteobacteria. nd = not done. 

Henkle-Duhrsen, K., Eckelt, V.H., Wildenburg, G., Blaxter, M. and Walter, R.D. (1998) Gene structure, activity and localization of a catalase from intracellular bacteria in Onchocerca volvulus. Molecular and Biochemical Parasitology 96, 69-81. 

O Hydrogen peroxide is often used to sterilize wounds. The fizzing that occurs is caused by catalase in the blood acting on the hydrogen peroxide. Bacteria that do not have catalase to disable the hydrogen peroxide are killed by this chemical. Humans are protected by the presence of catalase. Not all bacteria are killed by hydrogen peroxide, however, because some bacteria do have catalase. 

Some sulfate-reducing bacteria have been shown to contain SODs and catalases, but other species do not demonstrate the expected activities for these enzymes (Hatchikian et al. 1977 van Niel and Gottschal 1998 Dos Santos et al. 2000). The apparent absence of these enzymes can be rationalized on the basis that their catalytic dismutation reactions (Eqs. 10.1 and 10.2) generate dioxygen, which may be disadvantageous for strict anaerobes but raises the question of how these organisms protect themselves against transient air exposure. 

Hatchikian CE, LeGall J, Bell GR. 1977. Significance of snperoxide dismntase and catalase activities in the strict anaerobes, sulfate-redncing bacteria. In Michael AM, McCord JM,Fridovich I, editors. Snperoxide and snperoxide dismntase. New York Academic Press, p 159-72. 

The next largest group of catalases are the catalase-peroxidases, so named because they exhibit a significant peroxidatic activity in addition to the catalatic activity. They have been characterized in both fungi and bacteria and resemble certain (type I) plant and fungal peroxidases... 

The physiology of catalase expression and its control in bacteria, yeast, and plants has been reviewed elsewhere (2, 26, 27). The following precis is presented so that a summary of physiological information relevant to the detailed biochemistry is readily available. 

The early work on catalase expression was carried out largely in E. coli and revealed two main response mechanisms. One or the other or both responses have been identified in most other bacteria expressing a catalase. The expected and most obvious response is to oxidative stress. Addition of hydrogen peroxide directly or of ascorbate, which... 

Catalases have proven to be a treasure trove of unusual modifications. The first noted modification was the oxidation of Met53 of PMC to a methionine sulfone (77). Met53 is situated in the distal side active site adjacent to the essential His54 in a location where oxidation by a molecule of peroxide would not be unexpected. Among the catalases whose structures have been solved, PMC is unique in having the sulfone because valine is the more common replacement in other catalases. The sulfone does not seem to have a role in the catalytic mechanism and is clearly generated as a posttranslational modification. A small number of catalases from other sources, principally bacteria, have Met in the same location as PMC, and it is a reasonable prediction that the same oxidation occurs in those enzymes as well, although this has not been demonstrated. 

The catalase-peroxidases present other challenges. More than 20 sequences are available, and interest in the enzyme arising from its involvement in the process of antihiotic sensitivity in tuherculosis-causing bacteria has resulted in a considerable body of kinetic and physiological information. Unfortunately, the determination of crystallization conditions and crystals remain an elusive goal, precluding the determination of a crystal structure. Furthermore, the presence of two possible reaction pathways, peroxidatic and catalatic, has complicated a definition of the reaction mechanisms and the identity of catalytic intermediates. There is work here to occupy biochemists for many more years. 

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. ... 

These heteropentalenes are also toxic to bacteria cells Escherichia coli. Penetrating into the cells they are reduced by an enzyme system and then convert O2 to toxic O2 and H2O2 returning themselves to the initial state <89Mi 4ii-0l>. Activity as an oxygen promotor with catalase and superoxidase was found for (5 X = S) in concentrations down to 0.005 mM <89JAP8966120>. 

Hatchikian, C. E., Le Gall, J. Significance of superoxide dismutase and catalase activities in the strict anaerobes, sulfate reducing bacteria. In Superoxide and Superoxide Dismutases (Michelson, A. M, McCord, J. M., Fridovich, L, eds.), London-New York-San Francisco, Academic Press, 1977, pp. 159-172... 

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