First, the enzyme reacts with one peroxide equivalent resulting in oxidation of the haem iron to the oxyferryl, Fe(IV-0), centre and an organic radical, R', where R' is either the porphyrin or an amino acid-centred radical. Next, Compound I oxidizes one substrate molecule to give a substrate radical and Compound 11. Finally, Compound I1 is reduced by a second substrate molecule to the resting, ...

This study focuses on the mechanisms for hydrogen peroxide detoxification in Synechococcus sp. strain PCC 7942. To gain better understanding of the role of different routes of hydrogen peroxide detoxification, we inactivated TplA (thioredoxin-peroxidase-like), which we recently identified. In addition, we inactivated the gene encoding catalase-peroxidase and examined the ability to detoxify H(2...

Lignin peroxidase compound III (LiPIII) was prepared via three procedures: (a) ferrous LiP + O2 (LiPIIIa), (b) ferric LiP + 0; (LiPIIIb), and (c) LiP compound II + excess HzOz followed by treatment with catalase (LiPIIIc). LiPIIIa, h, and c each have a Soret maximum at -414 nm and visible hands at 543 and 578 nm. LiPIIIa, b, and c each slowly reverted to native ferric Lip, releasing stoichiomet...

White-rot basidiomycetes are one of the most important lignolytic microorganisms. These fungi have been reported to secrete three main classes of lignin degrading enzymes: lignin peroxidases (LiPs), manganese peroxidases (MnPs) and laccases. In this study, for the first time the lignin degrading capability of two plant pathogens i.e. Hyphodermella rosae and H. corrugata was evaluated using both...

Crown-gall tumor tissue cultures release peroxidase into the medium in response to the concentration of specific ions in the medium. This release is not due to diffusion from cut surfaces or injured cells. Calcium, magnesium, and ammonium were, in that order, most effective in increasing peroxidase release. The enzyme was demonstrated cytochemically on the cell walls and in the cytoplasm. Cell ...

Peroxidase, H2O2, and a halide form a powerful antimicrobial system in phagocytes and tissue fluids, and certain microorganisms can serve as the source of H2O2 for this system. H2O2-generating Lactobacillus acidophilus (LB+) is present in the vagina of most normal women and peroxidase has been detected in vaginal fluid. LB+ at high concentration is viricidal to HIV-1, and, at levels where LB+ i...

A set of bifunctional oxidase-peroxidases has been prepared by fusing four distinct oxidases to a peroxidase. Although such fusion enzymes have not been observed in nature, they could be expressed and purified in good yields. Characterization revealed that the artificial enzymes retained the capability to bind the two required cofactors and were catalytically active as oxidase and peroxidase. P...

Unusual peroxidase-positive granules exist in a particular cell type in the rat submaxillary gland during the first 2 wk after birth . The granules display remarkable substructure and clearly show cytochemical evidence of endogenous peroxidase activity . The cells containing the peroxidase-positive granules comprise portions of the terminal end pieces, or so-called "terminal tubules" (4), in th...

Utilizing cell preparations that contained greater than 90% eosinophils and sodium azide to inhibit the lysosomal enzyme peroxidase, studies of eosinophil bactericidal activity were undertaken. Eosinophils did not kill bacteria as well as neutrophils, principally because of a reduced phagocytic capacity. In contrast to neutrophils, eosinophils had high resting iodination activity but failed to ...

The enzymes responsible for reducing H2O2 were surveyed in 49 strains of Leptospira by using semiquantitative assays for catalase and peroxidase. The survey revealed a differential distribution of catalase and peroxidase activities between the two leptospiral complexes. The pathogenic Leptospira interrogans strains gave strong catalase and weak or negative peroxidase reactions. Conversely, the ...