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Applied Biochemistry and Microbiology (v.43, #5)
A.N. Bach: A great scientist and founder of biochemistry in Russia
by V. O. Popov; R. A. Zvyagil’skaya (pp. 475-480).
Initiation and inhibition of free-radical processes in biochemical peroxide systems: A review by D. I. Metelitza; E. I. Karasyova (pp. 481-505).
The role of complexes containing oxygen or peroxide in monooxygenase systems and models thereof, as well as in peroxidase-and quasi-peroxidase-catalyzed processes, has been reviewed. Pathways of conversion of these intermediate complexes involving single-electron (radical) and two-electron (heterolytic) mechanisms are dealt with. Peroxidase-catalyzed co-oxidation of aromatic amines and phenols is analyzed; inhibition and activation of peroxidase-catalyzed reactions are characterized quantitatively. Oxidation of chromogenic substrates (ABTS, OPD, and TMB) in the presence of phenolic inhibitors or polydisulfides of substituted phenols is characterized by inhibition constants (K i, μmol). Activation of peroxidase-catalyzed oxidation of the same substrates is characterized by the degree (coefficient) of activation (α, M−1), which was determined for 2-aminothiazole, melamine, tetrazole, and its 5-substituted derivatives. Examples of applied use of peroxidase-catalyzed enzyme and model systems are given (oxidation of organic compounds, chemical analysis, enzyme immunoassay, tests for antioxidant activity of biological fluids).
Reactive oxygen species and the strategy of antioxidant defense in fungi: A review by T. A. Belozerskaya; N. N. Gessler (pp. 506-515).
The level of reactive oxygen species (ROS) in the cell regulates the growth and differentiation of the fungal organism. This review considers the pathways of generation of the primary ROS and the defense methods used by fungi and yeasts against them as well as the involvement of thiol compounds in the antioxidant defense of the fungal cell. It is demonstrated that the adaptation of fungi to oxidative stress is tightly connected with the redox-dependent changes in the activities of antioxidant defense components.
Oxidative processes at initial stages of interaction of nodule bacteria (Rhizobium leguminosarum) and pea (Pisum sativum L.): A review by A. K. Glyan’ko; G. P. Akimova; L. E. Makarova; M. G. Sokolova; G. G. Vasil’eva (pp. 516-522).
A possible physiological mechanism of legume-Rhizobium symbiosis, consisting in regulation of the intensity of oxidative processes by the macrosymbiont in response to infection with Rhizobium, was analyzed using our own and published data. The results used in the analysis included data on the content of reactive oxygen species (O 2 ·− and H2O2), activity of antioxidant enzymes (superoxide dismutase, catalase, and peroxidase), and intensity of lipid peroxidation proceeding with the involvement of lipophilic phenolic compounds of the microsymbiont.
Laccase-mediator systems and their applications: A review by O. V. Morozova; G. P. Shumakovich; S. V. Shleev; Ya. I. Yaropolov (pp. 523-535).
The mechanism of operation of laccase-mediator systems (LMSs) in xenobiotic degradation mediated by “true” redox mediators and laccase enhancing agents is considered. Structural formulae of most common laccase mediators and compounds that can be used as agents enhancing the enzyme operation are presented. Examples of LMS application in biotechnology are described.
Hybrid Mn-peroxidases from basidiomycetes by A. V. Lisov; A. A. Leontievsky; L. A. Golovleva (pp. 536-543).
The Mn-peroxidase from the fungus Panus tigrinus 8/18 is a hybrid enzyme. It catalyzes both Mn2+-dependent and Mn2+-independent oxidation of organic substrates. The spectral properties of intermediates and the pathway of the catalytic cycle are typical of hybrid Mn-peroxidases. The enzyme catalyzes the “oxidase” reaction (NADH oxidation) without peroxide and with the presence of Mn2+, which takes part in hydrogen peroxide production via Mn3+ and preserves the enzyme from inactivation. With the presence of organic mediators, the hybrid Mn-peroxidase oxidizes nonphenolic compounds: aromatic alcohols and a nonphenolic lignin model compound. The degree of conversion of 2,4,6-trichlorophenol is higher with the presence of 1-hydroxybenzotriazole.
Dissimilatory nitrate reduction in fungi under conditions of hypoxia and anoxia: A review by E. V. Morozkina; A. V. Kurakov (pp. 544-549).
Recent progress in studies of anaerobic nitrate reduction and nitrous oxide formation in fungi has been reviewed. Current understanding of the biochemistry of nitrate and nitrite reduction to nitrous oxide and ammonium under oxygen limitation is presented, with emphasis on patterns of fungal co-denitrification, properties of the enzymes involved, and prevalence of nitrate respiration among fungal species.
Use of soybean peroxidase for the enzyme immunoassay of sulfamethoxipyridazine in milk by A. N. Berlina; A. V. Zherdev; B. B. Dzantiev; I. Yu. Sakharov (pp. 550-555).
An enzyme immunoassay with colorimetric detection of sulfamethoxipyridazine (SMP), the most widely used sulfamide, was developed with the soybean anionic peroxidase as an enzyme marker. The range of SMP detection is 1.3–63.0 ng/ml with a detection limit of 0.4 ng/ml. The root square deviation of detection results did not exceed 6%. It was demonstrated that 0.15% casein added to the working buffer prevented the effect of the milk matrix on the detection. The results obtained demonstrate that the assay developed is promising, displaying a sensitivity that exceeds the maximum permissible concentration of sulfamides in milk (100 μg/l) by several orders of magnitude.
Antioxidant enzyme complex of tissues of the bivalve Mytilus galloprovincialis Lam. under normal and oxidative-stress conditions: A review by A. A. Soldatov; O. L. Gostyukhina; I. V. Golovina (pp. 556-562).
The results of studies of tissue specifics of the enzymatic antioxidant complex of the bivalve Mytilus galloprovincialis Lam. are summarized. It is shown that the highest oxidative load is experienced by gills. The antioxidant complex of gills largely depends on environmental conditions than on the mollusk’s state, which allows this tissue to be used for ecological diagnostics. A decrease in the content of carotenoids in tissue s suppressed the activities of the key enzymes of antiradical defense—superoxide dismutase (SOD) and catalase—and is accompanied by a decrease in the reduced glutathione (GSH) pool. The state of the antioxidant complex of molluscan tissues under conditions of natural (spawning) and artificial (exposure to a cationic surfactant) oxidative stress was studied.