[Complex-formation between myeloperoxidase and fibronectin and its modulation by fibronectin ligands]. / Kompleksoobrazovanie mieloperoksidazy i fibronektina i ego moduliatsiia ligandami fibronektina.

Human blood plasma fibronectin immobilised on agarose in physiological interacts with soluble myeloperoxidase (Kd = 2.43 mM). Interaction of myeloperoxidase with fibronectin adsorbed on immobilised gelatin a, natural fibronectin ligand, resulted in formation more stable complex (Kd = 0.94 mM). The presence of thermoaggregated (but not native) IgG in the liquid phase increased a stability of the complex (0.06 mM). It is suggested that myeloperoxidase could represent a component of complex super molecular structure, real immune complex.

[Oxidation of ceruloplasmin by hypochlorite. The loss of blue color and preservation of oxidase activity]. / Okislenie tseruloplazmina gipokhloritom. Poteria goluboi okraski i sokhranenie oksidaznoi aktivnosti.

Ceruloplasmin oxidation by hypochlorite results in the bleaching of the protein solution; the oxidase activity remains, however, unchanged. Hypochlorite exerts a complex effect on the protein activity. After a short-term (5 min) incubation with hypochlorite the enzyme activity increases with a further progressive decrease. It is supposed that the oxidase activity of ceruloplasmin is not coupled with copper ions of the first type responsible for the blue staining of the protein solution. The low susceptibility of functional properties of ceruloplasmin to hypochlorite raises its potency as an antioxidative agent.

[Antioxidative properties and degradation of serum proteins by active oxygen forms (O2-., OCl-) generated by stimulated neutrophils]. / Antiokislitel'nye svoistva i degradatsiia belkov syvorotki aktivnymi formami kisloroda (O2-., OCl-), generiruemymi stimulirovannymi neitrofilami.

The ability of major serum proteins (albumin, immunoglobulin G) and free radical scavenger proteins (ceruloplasmin, superoxide dismutase, transferrin) to interact with O2-. and OCl- was studied. The interaction between serum proteins and OCl- was shown to be nonspecific and cause protein degradation. During SDS polyacrylamide gel electrophoresis ceruloplasmin and transferrin were degraded in the highest degree. Protein damage was also recorded by fluorescence changes. It is suggested that the damaging influence of active oxygen species secreted by stimulated neutrophils into the extracellular space can be abolished only by ceruloplasmin.

[Erythrocyte oxidative damage by myeloperoxidase. The protective action of serum proteins]. / Okislitel'noe povrezhdenie éritrotsitov mieloperoksidazoi. Zashchitnoe deistvie syvorotochnykh belkov.

Influence of main serum proteins (albumin, immunoglobulin G) and proteins-antioxidants (ceruloplasmin, transferrin, superoxide dismutase) on the oxidative damage of erythrocytes by myeloperoxidase and hypochlorite was investigated. The proteins were determined to act as protectors and decrease the degree of hemoglobin oxidation, ceruloplasmin and albumin possessing the highest antioxidant activity.

[Characteristics of luminol chemiluminescence induced by the catalytic action of myeloperoxidase]. / Osobennosti khemiliuminestsentsii liuminola, vozbuzhdaemoi kataliticheskim deistviem mieloperoksidazy.

The effects of pH, luminol myeloperoxidase and hydrogen peroxide concentrations on the intensity of luminol chemiluminescence induced by myeloperoxidase catalysis were investigated. It was found that the intensity of luminescence is proportional to the enzyme concentration (up to 8.10(-8) M) and reaches the saturation level at higher enzyme concentrations. The dependence of chemiluminescence intensity on [H2O2] is bell-shaped: at H2O2 concentrations above 1.10(-4) M the luminescence is inhibited with a maximum at neutral values of pH. Luminol at concentrations above 5.10(-5) M inhibits this process. It was demonstrated that the effects of singlet oxygen, superoxide and hydroxyl radicals on the chemiluminescence reaction are insignificant. Luminol oxidation in the course of the myeloperoxidase reaction is induced by hypochlorite.