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Mammalian catalase has been the subject of many classic biochemical studies. Despite our detailed knowledge of its functional mechanisms and its three-dimensional structure, however, several unexpected features of mammalian catalase have been recently discovered. For example, some mammalian catalases seem to have oxidase activity and produce reactive oxygen(More)
The reduced activity of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate; NADP+ 1-oxidoreductase; G6PF) in Mediterranean erythrocytes explains the precarious equilibrium of the hexose monophosphate pathway (HMP) and the susceptibility of these cells to haemolytic agents. G6PD-deficient erythrocytes, in steady-state conditions, have a low NADPH/NADP+(More)
Catalases (H2O2:H2O2 oxidoreductase, EC from many species are known to be tetramers of 60,000-dalton subunits, with four heme groups per tetramer. Previous authors have determined the amino acid sequence and three-dimensional structure of bovine liver catalase. Studies of the regulation of the pentose phosphate pathway led the present authors to a(More)
The discovery of the C282Y and H63D point mutations in the hereditary hemochromatosis-associated HFE gene allows us to study the molecular basis of congenital and acquired iron overload disorders. In hereditary hemochromatosis an increased frequency of the C282Y and, to a lesser extent, of the H63D mutations has been established, but their role in other(More)
Familial Hodgkin's disease (FHD) is estimated to represent approximately 4.5% of all cases of Hodgkin's disease (HD). Shared environmental factors, such as Epstein-Barr virus and other viral agents, and genetic determinants have all been proposed to explain familial aggregation of HD. In order to compare the characteristic features of FHD with those of the(More)
Serum LDH levels have been found to be significantly increased in non-Hodgkin lymphoma (NHL) patients, both histiocytic and lymphocytic. The duration of survival of NHL negatively correlates with the level of serum lactic dehydrogenase (LDH), and statistical analysis reveals that patients with lower levels of LDH have a longer survival rate than the(More)
A solid-phase radioimmunoassay for human glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase; EC was developed that allowed the specific activity of this enzyme protein to be measured in lysates from whole erythrocyte populations, in lysates from erythrocytes of different ages, and in purified samples. The enzyme was(More)
NADPH is known to be tightly bound to mammalian catalase and to offset the ability of the substrate of catalase (H2O2) to convert the enzyme to an inactive state (compound II). In the process, the bound NADPH becomes NADP+ and is replaced by another molecule of NADPH. This protection is believed to occur through electron tunneling between NADPH on the(More)
Genetic deficiencies of glucose-6-phosphate dehydrogenase (G6PD) and NADPH predispose affected erythrocytes to destruction from peroxides. Conversely, genetic deficiencies of catalase do not predispose affected erythrocytes to peroxide-induced destruction. These observations have served to strengthen the assumption that the NADPH/glutathione/glutathione(More)
Catalase (H2O2:H2O2 oxidoreductase, EC is of historical interest for having been the subject of some of the earliest investigations of enzymes. A feature of catalase that has been poorly understood for several decades, however, is the mechanism by which catalase remains active in the presence of its own substrate, hydrogen peroxide. We reported(More)