Cationic liposomes composed of sphingomyelin, cholesterol, and stearylamine were prepared with horseradish peroxidase trapped inside. Stable particles were formed in which 10-12% of the enzymic activity appeared to be located at, or near, the outer surface of the liposome. Adsorption and uptake of liposomes by HeLa cells were followed cytochemically by electron microscopy and quantitated by enz...

Diethylstilbestrol is carcinogenic in rodents and in humans and its peroxidatic oxidation in utero has been associated with its carcinogenic activity. Horseradish peroxidase-catalyzed oxidation of [14C]diethylstilbestrol and [14C]diethylstilbestrol analogs induced binding of radiolabel to DNA only when the compound contained a free hydroxy group (Metzler, M., and Epe, B. (1984) Chem. Biol. Inte...

mercury is one of the three major environmental metal poisons, and mercuric chloride is a highly reactive compound which can harm cells by a variety of mechanisms including direct interaction with sulphydryl groups of proteins and enzymes, therefore affecting the enzymatic activity. this study focused on the effect of hg++ on horseradish peroxidase (donor: hydrogen peroxide oxidoreductase, ec 1...

Low temperature visible spectra of Compounds I from peroxidases reconstituted with protohemin, 2-formyl-4-vinyldeuterohemin, 2-vinyl-4-formyldeuterohemin, 2,4-dimethyldeuterohemin, and 2,4-diacetyldeuterohemin reveal that these Fe(IV) porphyrin pi-cation radicals take the 2A2u of peroxidase-type electronic ground state. Compound I of deuterohemin horseradish peroxidase, however, takes the 2A1u ...

Paramagnetic complexes of iron (III), manganese (II), and cobalt (II) protoporphyrins IX and apohemoproteins react with nitric oxide to form spectroscopically distinct compounds. Optical and electron paramagnetic resonance (EPR) studies suggest that a l-electron transfer between nitric oxides and metal ions which occurs in these reactions results in the formation of spin-paired complexes of the...

Paramagnetic complexes of iron (III), manganese (II), and cobalt (II) protoporphyrins IX and apohemoproteins react with nitric oxide to form spectroscopically distinct compounds. Optical and electron paramagnetic resonance (EPR) studies suggest that a l-electron transfer between nitric oxides and metal ions which occurs in these reactions results in the formation of spin-paired complexes of the...

The hydroperoxide-supported N-demethylation reactions catalyzed by horseradish peroxidase have been characterized in detail. The ethyl hydroperoxide-supported N-demethylation of N,N-dimethylaniline by horseradish peroxidase resulted in the formation of equimolar amounts of N-methylaniline and formaldehyde with no other products detectable by high performance liquid chromatography analysis of th...

The hydroperoxide-supported N-demethylation reactions catalyzed by horseradish peroxidase have been characterized in detail. The ethyl hydroperoxide-supported N-demethylation of N,N-dimethylaniline by horseradish peroxidase resulted in the formation of equimolar amounts of N-methylaniline and formaldehyde with no other products detectable by high performance liquid chromatography analysis of th...

For the purpose to obtain the information of the mechanism of protein uptake by the tumor cells, some cytochemical and electron microscopic observations were carried out on Ehrlich ascites tumor cells incubated with horseradish peroxidase (basic hemoprotein, molecular weight approximately 40,000) in vitro. In the earlier periods of the incubation peroxidase was found to be adsorbed on some area...