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.     

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.     

Superoxide radical inhibits catalase

Catalase was inhibited by a flux of O2- generated in situ by the aerobic xanthine oxidase reaction. Two distinct types of inhibition could be distinguished. One of these was rapidly established and could be as rapidly reversed by the addition of superoxide dismutase. The second developed slowly and was reversed by ethanol, but not by superoxide dismutase. The rapid inhibition was probably due to conversion of catalase to the ferrooxy state (compound III), while the slow inhibition was due to conversion to the ferryl state (compound II). Since neither compound III nor compound II occurs in the catalatic reaction pathway, they are inactive. This inhibition of catalase by O2- provides the basis for a synergism between superoxide dismutase and catalase. Such synergisms have been observed in vitro and may be significant in vivo.     

Fatty acyl coupled catalase

Bovine liver catalase (hydrogen-peroxide:hydrogen peroxide oxidoreductase, EC 1.11.1.6) was derivatized by 9″(10″)-[4′-{2-(4,6-dichloro-1,3,5-triazinyl)oxy}butoxy]stearic acid and the fatty acyl-coated enzyme was separated from native catalase and excess reagent by hydroxyapatite chromatography. The derivatization of catalase resulted in coupling the long-chain fatty acyl residues to lysine, histidine and arginine, while other amino acids remained essentially unaffected. The fatty acyl-coated enzyme was water soluble at pH > 7.0 but became octanol and ether soluble at pH < 6.5. The derivatized enzyme retained 50–80% of the catalatic- and peroxidative-specific activities. The free carboxyl function of the coupled long-chain fattyl acyl residues could serve as substrate for ATP-dependent CoA-thioesterification catalyzed by the rat liver microsomal long-chain fatty acyl-CoA synthase.     

Nomenclature for catalase genes

Summary Gene product: catalase (H₂O₂:H₂O₂ oxidoreductase, EC 1.11.1.6) Mnemonic:Cat0 Gene product number:2.1.11.1.6