Classical catalase: ancient and modern

This review describes the historical difficulties in devising a kinetically satisfactory mechanism for the classical catalase after its identification as a unique catalytic entity in 1902 and prior to the breakthrough 1947 analysis by Chance and co-workers which led to the identification of peroxide compounds I and II. The role of protons in the formation of these two ferryl complexes is discussed and current problems of inhibitory ligand and hydrogen donor binding at the active site are outlined, especially the multiple roles involving formate or formic acid. A previous mechanism of NADPH-dependent catalase protection against substrate inhibition is defended. A revised model linking the catalytic ('catalatic') action and the one-electron side reactions involving compound II is suggested. And it is concluded that, contrary to an idea proposed in 1963 that eukaryotic catalase might be a 'fossil enzyme', current thinking gives it a central role in the redox protective processes of long term importance for human and other eukaryotic and prokaryotic life.     

Genetic studies of murine catalase: Regulation of multiple molecular forms of kidney catalase

Starch gel electrophoresis of kidney catalase in inbred strains C3H and C57BL/6, their F₁ hybrid, and first and second backcross generations demonstrated that single-component (type A) v. multiple-component (type B) electrophoretic patterns are controlled by a single locus. The type A electrophoretic pattern is dominant. Twenty-five inbred strains of mice were classified according to their kidney catalase electrophoretic pattern. The data indicate that the segregating genetic factor determines a specific substance in the type A kidney which affects the electrophoretic mobility of catalase. A comparison of the F₁ hybrid enzyme with a 1:1 mixture of C3H and C57BL/6 enzyme showed that the alteration of electrophoretic mobility is the result of posttranslational modification of the catalase molecule. An association of kidney catalase electrophoretic pattern and the H-2 ^k haplotype indicates that the locus controlling the electrophoretic pattern is most likely located on chromosome 17 in close proximity to the H-2 complex.     

Immobilized catalase: deactivation and reactor stability

The quasi-steady behavior of a continuous flow reactor in which hydrogen peroxide is decomposed by immobilized catalase is investigated. Under certain conditions, reactors involving such substrate-inhibited, self-poisoning reactions are susceptible to suddne failure and the reactor moves catastrophically from high- to low-conversion quasi-steady states. This exchange-of-steady-states phenomenon is ex-amined in the light of experimental evidence for the enzyme catalase from bovine liver. (c) 1993 John Wiley & Sons, Inc.     

Human catalase: looking for complete identity

Catalases are well studied enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. The ubiquity of the enzyme and the availability of substrates made heme catalases the focus of many biochemical and molecular biology studies over 100 years. In human, this has been implicated in various physiological and pathological conditions. Advancement in proteomics revealed many of novel and previously unknown features of this mysterious enzyme, but some functional aspects are yet to be explained. Along with discussion on future research area, this mini-review compile the information available on the structure, function and mechanism of action of human catalase.     

Murine catalase phenotypes

An examination of three inbred strains of mice differing with respect to liver and kidney catalase activity reveals two distinct genetic factors controlling the level of liver catalase activity. The first genetic factor controls the catalytic activity of the enzyme. Specific activity of purified enzyme from C57BL/6 and C57BL/Ha strains is 60% of that of the DBA/2 strain. The second factor controls the content of liver catalase. Liver catalase of C57BL/Ha is degraded in vivo at a rate one half that of liver catalase of DBA/2 and C57BL/6, resulting in the accumulation of twice as many catalase molecules in C57BL/Ha. The factor affecting turnover of catalase is apparently specific for catalase of liver since no differences exist in kidney catalase levels between C57BL/Ha and C57BL/6. Furthermore, this factor does not appear to alter the metabolism of total liver protein since no substantial difference in the turnover rate of liver protein is observed among the strains. It is particularly significant that the genetic factor affecting the amount of liver catalase does so by altering the rate of catalase degradation rather than the rate of synthesis, confirming the previously published report of Rechcigl and Heston (1967). Thus, these studies emphasize that the quantity of an enzyme in animal cells is a balance between the rate of synthesis and the rate of degradation of the enzyme.This paper was presented at a symposium entitled Genetic Control of Mammalian Metabolism held at The Jackson Laboratory, Bar Harbor, Maine, June 30–July 2, 1969. The symposium was supported in part by an allocation from NIH General Research Support Grant FR 05545 from the Division of Research Resources to The Jackson Laboratory.This investigation was supported by USPHS Research Grant GM 14931 from the Division of General Medical Sciences, and Grants PF-373 and P-427 from the American Cancer Society.     

Helicobacter pylori catalase

Helicobacter pylori is the major aetiological agent of gastroduodenitis in humans. Due to the potential importance of catalase in the growth and survival of Helicobacter pylori on the surface of inflamed mucosae, we have characterized catalase from H. pylori as a prelude to further studies on the function of the enzyme in vivo. The catalase activity of H. pylori was significantly affected by the presence of blood, serum or erythrocytes in the growth medium: the greatest activity was expressed when the bacterium was grown on medium containing serum. H. pylori catalase is a tetramer with a subunit Mr of 50,000. The enzyme had a pI of 9.0-9.3, was active over a broad pH range and was stable at 56 degrees C. It was non-competitively inhibited by sodium azide, and had no detectable peroxidase activity. The Km for the purified catalase was measured as 43 +/- 3 mM-H2O2 and the V as 60 +/- 3 mmol H2O2 min-1 (mg protein)-1. The native catalase has absorption maxima at 280 nm and 405 nm with further minor shoulders or peaks at 510 nm, 535 nm and 625 nm, consistent with the presence of an iron-porphyrin prosthetic group.     

Purification and characterization of liver catalase in acatalasemic beagle dog: comparison with normal dog liver catalase

Catalase from acatalasemic dog liver was purified to homogeneity and its properties were compared with those of normal dog liver catalase. The purified acatalasemic and normal dog liver catalases were found to have the same molecular weight (230,000 Da) and isoelectric point (pI: 6.0-6.2) and both enzymes contained four hematins per molecule. The catalytic activity of catalase from acatalasemic dog was normal. Furthermore, there was no difference between the acatalasemic and normal dog catalases in the binding affinity to NADPH (apparent Kd: 0.11-0.12 microM) and in the sensitivity to oxidative stress by hydrogen peroxide, the normal substrate of catalase. The acatalasemic dog enzyme was stable only in a narrow pH range (pH 6-9) although the normal enzyme was stable in a wide pH range (pH 4-10). Acatalasemic dog liver catalase also showed a slight low thermal stability at 37 degrees C and the heat-lability was remarkable at 45 degrees C, compared to the normal dog enzyme. These results indicated that the acatalasemic dog catalase is catalytically normal although it is associated with an unstable molecular structure.     

Evaluation of a catalase inhibitor in the developmental regulation of maize catalase

A protein which has been shown to inhibit catalase in vitro appears to vary inversely with catalase activity in the maize scutellum during early sporophytic development when assayed using a catalase inhibition assay. This result suggested that the inhibitor protein may play a direct role in regulating catalase activity during this time period. Four experimental approaches were used to evaluate this putative regulatory role, including immunological quantitation of individual catalase isozymes during germination using rocket immunoelectrophoresis, perturbation of normal catalase expression with hydrogen peroxide or allylisopropylacetamide (AIA), examination of a mutant line with an altered catalase developmental program, and direct radioimmunoassay of the inhibitor protein during germination. The results of these experiments indicate that the quantitative changes in catalase activity during development are not mainly due to changes in the expression of the catalase inhibitor. Other possible roles of this protein in catalase regulation are discussed.     

Crystalline bovine liver catalase

A crystalline form of bovine liver catalase has been found in which one of the molecular 2-fold axes is incorporated into the crystal symmetry.