Microsporidia constitute a group of extremely specialized intracellular parasites that infect virtually all animals. They are highly derived, reduced fungi that lack several features typical of other eukaryotes, including canonical mitochondria, flagella, and peroxisomes. Consistent with the absence of peroxisomes in microsporidia, the recently completed genome of the microsporidian Encephalito...

For the purpose to clarify further the residual catalase in the blood cell ghost, the ghost has been applied to Cyanogum and starch block electrophoresis and the results are briefly summarized as follows. 1. It has been demonstrated that after Cyanogum electrophoresis of the ghost after several washings, bubbling due to enzymatic reaction of catalase occurs near the points of origin, when the p...

Histoplasma capsulatum produces an extracellular catalase termed M antigen, which is similar to catalase B of Aspergillus and Emericella species. Evidence is presented here for two additional catalase isozymes in H. capsulatum. Catalase A is highly similar to a large-subunit catalase in Aspergillus and Emericella species, while catalase P is a small-subunit catalase protein with greatest simila...

Activated oxygen species have been demonstrated to be the important agents in oxygen toxicity by disrupting the structural and functional integrity of cells through lipid peroxidation events, DNA damage and protein inactivation. The biological consequences of free radical damage have long been hypothesized to be a causal agent in many aging-related diseases. Catalase (H2O2:H2O2 oxidoreductase; ...

Previous studies in our laboratory have shown that the elevation of reactive oxygen species levels and the repression of the antioxidant enzyme, catalase, played a critical role in the in vitro progression of benign papilloma cells to malignant carcinoma cells. Catalase message, protein levels, and activity levels were found to be downregulated in the malignantly progressed cells. The goal of t...

The enzyme catalase protects aerobic organisms from oxygen-free radical damage by converting hydrogen peroxide to molecular oxygen and water before it can decompose to form the highly reactive hydroxyl radical. Hydroxyl radicals are the most deleterious of the activated oxygen intermediates found in aerobic organisms. If formed, they can react with biological molecules in their proximity; the e...

Several rat and mouse hepatomas and the liver and kidneys of the host animals were assayed for catalase activity. Little or no activity could be demonstrated in the subcutaneously transplanted Novikoff hepatoma, Hepatoma LC18, and Hepatoma 3683 of rats, and in a number of transplanted hepatomas of mice and hamsters. A relatively high activity was found, however, in the transplanted Hepatoma 512...

Catalase-peroxidase (KatG) is an enzyme capable of utilizing both catalase and peroxidase activity to break down hydrogen peroxide. Catalase activity by the enzyme generally dominates, but peroxidatic electron donors have been shown to stimulate catalase activity, likely by rescuing catalase-inactive intermediates resulting from off-pathway electron transfer. To investigate tryptophan 438 as a ...

Peroxidatic activity of catalase (E .C .1 .11 .1 .6) was discovered by Keilin and Hartree (1), and it has been firmly established that, catalase oxidizes various substrates such as ethanol, methanol, nitrite, and formate (2-4) . Crystalline beef liver catalase, used as an enzyme tracer (5), and the peroxisomal catalase (6, 7) have been visualized cytochemically by a modification of the 3,3'diam...

Previous work with Pseudomonas aeruginosa showed that catalase activity in biofilms was significantly reduced relative to that in planktonic cells. To better understand biofilm physiology, we examined possible explanations for the differential expression of catalase in cells cultured in these two different conditions. For maximal catalase activity, biofilm cells required significantly more iron...