A catalase

The hydrogen peroxide produced in the glucose oxidase catalyzed reaction contains an antibacterial action. The addition of a catalase converts the hydrogen peroxide to water and oxygen. 

The Cell link Concept was invented and patented in 1994. Since then BIM/Cellkem has developed the invention to a complete concept including a Catalase/Residual peroxide meter from BTG. This is now a turnkey equipment that can be installed anywhere where Catalase needs to be controlled. 

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. 

In the absence of electron donors, complexes 1 display a catalase-like activity (Eq. (17)). Dioxygen evolution can be visually observed at [H202] >0.01M. This catalytic feature has been studied kinetically by monitoring the initial rates of 02 formation with a Clark electrode (53). 

Dos Santos WG, Pacheco I, Liu MY, et al. 2000. Purification and characterization of an iron superoxide dismutase and a catalase from the sulfate-reducing bacterium Desulfovibrio gigas. J Bacteriol 182 796-804. 

Several heme-containing proteins, including most peroxidases 12), have been observed to exhibit a low level of catalatic activity, with the chloroperoxidase from Caldariomyces fumago exhibiting the greatest reactivity as a catalase (13-15). Despite the fact that there is as yet only one such example to consider, it provides an alternate mechanism for the catalatic reaction and is addressed in this review. It was first characterized for its ability to chlorinate organic substrates in the presence of chloride and hydrogen peroxide at acid pH, but was later found... 

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... 

Detailed structural information about Type A catalases is available... 

Fig. 18. Mechanisms of compound I formation in type B catalases (based on yeast CCP) (see also Section IV,F and Fig. 7) (A) type A catalases (B) and chloroperoxidase (C).

In the type A catalases, there are only two active site residues in locations where they can influence the reaction, a histidine and an asparagine. A mechanism for compound I reduction in catalases was... 

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,... 

However, a catalase that removes hydrogen peroxide has been detected in T foetus, but not in T. vaginalis (Page-Sharp et al. 1996). 

The prepolymer used for this study was an MDI-based preparation (Suprasec 1002) from Huntsman PU, Brussels, Belgium. Immobilization of the enzyme was accomplished by coating the inside structure of a reticulated foam with an acetone solution of a hydrophilic polyurethane prepolymer. A 45-pore/in. reticulated foam cut into sheets 0.25 in. thick was used. The coated reticulated foam was immersed in a catalase solution (5 pg/ml) at 4°C and left in the solution for 1 hour to ensure a complete solution. It is known that both the water and some functionality in the catalase react with the isocyanate groups to cause polymerization (the water-isocyanate reaction) and chain termination (the catalase reaction). Controlling the relative concentrations and temperature permits control of the physical properties of the composite and the ability of the foam to function as an enzyme. 

Cataract was induced in eyes of rabbits by 3-aminotriazole, a catalase inhibitor, whereby the H Oj concentration was raised and (Cu,Zn)-SOD partially inactivated. ... 

For this type of sensor, a catalase-free glucose oxidase must be used. In such a case, the hydrogen peroxide produced by the reaction with oxygen remains in the selective layer and can be detected by oxidation according to the reaction... 

L. Campanella, M.P. Sammartino, M. Tomassetti and S. Zannella, Hydroperoxide determination by a catalase OPEE application to the study of extra virgin olive oil rancidification process, Sens. Actuators B Chem., 76(1-3) (2001) 158-165. 

Another dinuclear, high oxidation state complex, [MnIV(salpn)( j.2-0)]2, 63, contains a MnIVMnIV center, an oxidation state level even higher than those known for catalases. Nevertheless complex 63 has catalase activity (1000 turnovers without decomposition) and follows a catalase pathway (Scheme 7) similar to that of L. plantatarum catalase (Scheme 1) [109]. 

According to Rossmann, the C2H5OOH molecule is converted to one CH3CHO molecule and H20, whereas a catalase reaction requires two H202 molecules for H20 and 02 synthesis. Thus, ethanol produced in complex V synthesis is immediately oxidized to aldehydes. In the analysis of both reactions of special attention is the circumstance that in a stoichiometric aspect, the Rossmann reaction represents dehydrogenation ... 

A catalase mimic, similar to that described above, was synthesized on five forms of aluminum oxide a-, [3-, acidic, basic and neutral. The neutral and basic forms of A1203 were found to be the most active sorbents. Prior to adsorption, hemin was dissolved on an aqueous alcohol solution (pH 9), where it transformed to hematin, and then applied on A1203 forming catalase mimic PPFe3+0H/Al203. According to this technique, iron protoporphyrin was applied on Si02. 

Figure 8.2 shows an electrochemical system - a model of a catalase-biomimetic sensor, consisting of the reference electrode (Ag/AlCl/Cl ) and biomimetic electrode. In this system, the electrochemical potential changed as a result of mimetic electrode interaction with... 

Another type of thin film device consists of four 0.5 x 0.5 mm2 platinum working electrodes and a Ag/AgCl reference electrode made on a 0.3 mm glass carrier. The enzymes were immobilized onto the working electrodes in a photo crosslinked pHEMA membrane and additionally covered by a diffusion limiting and a catalase containing top layer [77]. 

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