Laboratory of Biological Oxidation

Home Page

History

Address

Basic Achievements
	The xenobiotics oxidation by plant cytochrome P450-containing monooxygenase systemhave been studied. It has been revealed that in plant cells the monooxygenase system exists in soluble and membrane-bound forms
	It was stated that the same fund of cytochrome P450-containing monooxygenase system must be participating in plant intracellular metabolic (e.g. biosynthesis of phenolic compounds) and detoxification processes. It was shown that xenobiotic hydrophobicity is the main factor which determines the quantity of cytochrome P450 switching from biosynthesis to detoxification
	It was shown that efficiency of cytochrome P450 induction by xenobiotics depends on the chemical nature of intermediates formed at inductor oxidation, particularly, the higher is acivity of intermediate the less occurs cytochrome P450 formation. Under certain conditions (e.g. plant aging, aeration, action of radical intermediates) plant cytochrome P450 looses NADPH-dependent oxidation ability and catalyzed oxidation reactions at presence of H₂O₂, i.e. monooxygenase mechanism of xenobiotic oxidation is changed by peroxidase
	The connection between detoxification and cell energetical processes has been revealed. It has been shown that in the respiratory chain of mitochondria at electrons free transport the electrons are used for detoxification of penetrated into the cell xenobiotics. In these conditions migration of electrons from mitochondrial respiratory chain complex III to cytochrome b₅ of microsomal redox-chain takes place. When the monooxygenase system does not participate in detoxification process, the initial components of monooxygenase system (NADPH cytochrome P450 reductase and cytochrome b₅) transfer the reducing equivalents to mitochondrial bc₁-complex. Existence of the mentioned mechanosm stipulates insertion of NADPH reducing equivalents besides NADH in cell energetics which is very important for the plant having rich source of NADPH via photosynthesis
	The enzymatic transformation of 2,4,6-trinitrotoulene (TNT) mainly involved NAD(P)H-nonspecific nitroreductase acting on the TNT nitro groups. Nitroreductase activity was revealed in root cell cytosol and expression was strongly induced by plant cultivation on TNT-containing media. A plant’s nitroreductase activity and its ability to uptake TNT from aqueous solutions were correlated. These results suggest that plant nitroreductase activity may serve as a biochemical criteria to select plants for phytoremediation of soils contaminated with TNTs
	According to the laboratory conception, the xenobiotic oxidation in plant proceeds via the interchange of oxidative enzymes (basically cytochrome P450-containing monooxygenase, peroxidase, phenoloxidase). We suppose that plant cytochrome P450 plays the important role in plant adaptation to stress factors. Currently the works are carried out to experimentally corroborate the mentioned hypothesis