Catalase action

In 1938 Keilin and Hartree (42) proposed the following scheme for the catalase reaction with hydrogen peroxide  

Chance (16a) recently demonstrated the formation of an intermediate compound of catalases and hydrogen peroxide. The compound had many properties in common with the intermediate compound of hydrogen peroxide and peroxidase. The spectrum could be determined in the region of the Soret band showing a small shift of the band toward the red. The rate of formation of this compound was 3 X lO liter mole sec, exceeding the value required by the Michaelis theory for catalase activity. Without the addition of acceptor the compound decomposed slowly at about the same rate as the peroxidase-peroxide compound. The catalase activity increases the equilibrium constant to 1 X 10 mole liter h The inter- 

Theorell, H., Bergstrom, S., and Akeson, A., Arkiv Kemi Mineral. Geol., A16, 

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The hydrogen peroxide produced by SOD is then removed by either catalase action or GSH peroxidase. The products are water and oxygen or water and GSSG (Figs. 6.10 and 6.18). 

The temperature coefficient of catalase action is relatively small but reactions leading to inactivation are greatly influenced by temperature. 

Senter (313) studied the kinetics of catalase action by plotting the data obtained at 5, 10, 20, and 30 minutes of reaction time. In 1924 Hennichs (175) based the Kat.f. unit (see p. 362) on measurements at 5, 10, 15, 20, and 25 minutes. Von Euler and Josephson (140) changed this to 3, 6, 9, and 12 minutes. Their test was to become the standard assay for catalase activity. The choice of such long reaction times was quite unfortunate, because the rate of the catalytic reaction decreases considerably even before the first measurement is made (71). Extrapolation of the data to zero time, suggested by Sumner (338), solved the problem only to a small extent. By plotting experimental data obtained in the first minute of the reaction, Bonnichsen et al. (71) illustrated the drawbacks of extrapolating the results obtained from long reaction times. 

In summary, it may be said that the determination of residual hydrt en peroxide offers no advantage for routine determinations of peroxidase over the more conventional methods employing donor oxidation. And while several authors claim to have found methods of inhibiting catalase action during these assays, no reliable technique to do this has been well substantiated. The advantage of methods which measure residual substrate consists in avoiding any influence of oxidase activity on the results of the assay. 

Rieche (28) published some years ago the absorption spectra and molecular extinction coefficients of hydrogen and alkyl hydrogen peroxides that are reproduced here (Fig. 2). These data may be used for routine assays of peroxide solutions, for routine assays of catalase activity, and for studies of catalase activity in connection with the mechanism of catalase action. 

The hydrogen peroxide produced in the glucose oxidase catalyzed reaction has an antibacterial action. If the presence of hydrogen peroxide is undesirable in the product, catalase is added to remove the peroxide. 

Under most conditions in vivo, the peroxidase activity of catalase seems to be favored. Catalase is found in blood, bone marrow, mucous membranes, kidney, and fiver. Its function is assumed to be the destruction of hydrogen peroxide formed by the action of oxidases. 

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... 

Lovstad, R.A. (1984). Catecholamine stimulation of copper-dependent haemolysis protective action of superoxide dismutase, catalase, hydroxyl radical scavengers and scrum proteins (ceruloplasmin, albumin and apotransferrin). Acta Pharmacol. Toxicol. 54, 340-345. 

Enzyme-mediated action, by sulfhydryl and phenylalanine-lyase (PAL) enzymes as well as by other enzymes such as cellulase, catalase, peroxidase, phosphorylase and pectolytic enzymes ... 

Garlic s proven mechanisms of action include (a) inhibition of platelet function, (b) increased levels of two antioxidant enzymes, catalase and glutathione peroxidase, and (c) inhibition of thiol enzymes such as coenzyme A and HMG coenzyme A reductase. Garlic s anti-hyperlipidemic effects are believed to be in part due to the HMG coenzyme A reductase inhibition since prescription medications for hyperlipidemia have that mechanism of action (statins). It is unknown whether garlic would have the same drug interactions, side effects, and need for precautions as the statins. 

Investigate catalase, and compare its action with the actions of several... 

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