[Role of antioxidants in electro catalytic activity of cytochrome P450 3A4].

The electrochemical analysis of cytochrome Р450 3А4 catalytic activity has shown that vitamins C, A and Е influence on electron transfer and Fe3+/Fe2+ reduction process of cytochrome Р450 3А4. These data allow to assume possibility of cross effects and interference of vitamins-antioxidants with drugs metabolised by cytochrome Р450 3А4, at carrying out of complex therapy. This class of vitamins shows antioxidant properties that lead to increase of the cathodic current corresponding to heme reduction of this functionally significant haemoprotein.

[Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes b5].

Molecular interactions between proteins redox partners (cytochromes P450 3A4, 3A5 and cytochrome b5) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes P450 3A4 and 3A5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b5: the microsomal (b5mc) and mitochondrial (b5om) forms of this protein, as well as with 2 "chimeric" proteins, b5(om-mc), b5(mc-om). Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor.

[Electrochemical measurement of intraprorein and interprotein electron transfer].

Intramolecular and intermolecular direct (unmediated) electron transfer was studied by means of electrochemical techniques in flavohemoprotein cytochrome P450 BM3 (CYP102A1 from Bacillius megaterium) and between cytochrome b5 and cytochrome c. Flavohemoprotein cytochrome P450 BM3 was immobilized on a screen printed graphite electrode, modified with a biocompatible nanocomposite material based on the didodecyldimethylammonium bromide DDAB and gold nanoparticles. Analytical characterictics of DDAB/Au/P450 BM3 electrodes were studied with cyclic voltammetry and square wave voltammetry.

[Electrochemical sensor systems based on one dimensional (1D) nanostructures for analysis of bioaffinity interactions].

It was shown that modification of screen printed graphite electrodes with gold nanoparticles (AuNPs) decorated Pb nanowires (PbNWs) demonstrates the enhancement of sensor's analytical characteristics such as effective surface area, electro catalytic properties and heterogeneous electron transfer kinetics. The reason for such improvement may be the synergistic effect ofAuNPs and PbNWs. Nanowires ensembles on electrode surface were employed for the detection of hemeproteins cytochrome P450 2B4, cytochrome c, and cardiac myoglobin in human plasma.

[Screening of potential substrates or inhibitors of cytochrome P450 17A1 (CYP17A1) by electrochemical methods].

The electrochemical reduction of the recombinant form of human cytochrome P450 17A1 (CYP17A1) was investigated. Hemeprotein was immobilized on electrode modified with biocompatable nanocomposite material based on the membrane-like synthetic surfactant didodecyldimethylammonium bromide (DDAB) and gold nanoparticles. Analytical characteristics of DDAB/Au/CYP17A1 electrodes were investigated with cyclic voltammetry, square wave voltammetry, and differential pulse voltammetry.

[The influence of vitamin B group on monooxygenase activity of cytochrome P450 3A4: pharmacokinetics and electro analysis of catalytic properties].

It was shown that vitamin B group permit to shorten the longitude of diclofenak therapy and to reduce the daytime dose of this drug. All three schemes of diclofenac treatment - only diclofenac, diclofenac plus 2 tablets of Gitagamp (mixture of vitamin B group), and diclofenac plus 4 tablets of Gitagamp--gave maximum value of diclofenal in blood through 1 hour after treatment. In the case of diclofenak treatment without vitamins Cmax corresponds to 1137.

[Electrochemical immunoanalysis of cardiac myoglobin].

Method targeting the direct monitoring of myoglobin based on analysis of electrochemical parameters of modified electrodes were proposed. Method of direct detection is based on interaction of myoglobin with anti-myoglobin with subsequent electrochemical registration of hemeprotein. Myocardial infarction biomarker myoglobin was quantified at biological level using screen printed electrodes modified with gold nanoparticles stabilized with didodecyldimethylammonium bromide (DDAB) and antibodies.

[Sensor systems for medical application based on hemoproteins and nanocomposite materials].

Recent advances in nanotechnologies stimulate the development of sensor systems based on nanocomposite materials. This review discusses the prospects and challenges of sensors coupled with functionally important for medicine hemoproteins and nanoscale materials. Authors summarized their own experimental results and literature data on hemoprotein-based sensor systems.

[Nanoelectrochemistry of cytochrome P450s: direct electron transfer and electrocatalysis].

The present study demonstrates the direct electron transfer between cytochrome P450 2B4 (CYP2B4), P450 1A2 (CYP1A2), sterol 14alpha-demethylase (CYP51MT) and screen printed graphite electrodes, modified with gold nanoparticles and didodecyldimethylammonium bromide (DDAB). Electrodetection of heme proteins is possible when 2-200 pmol P450/electrode were adsorbed on the surface of nanostructured electrochemical interfaces. Electron transfer, direct electrochemical reduction and interaction with P450 substrates (oxygen, benzphetamine, lanosterol) and inhibitor ketoconazole were analyzed using cyclic voltammetry (CV), square wave (SWV) or differential pulse (DPV) voltammetry, amperometry.

[Electrochemical reduction of cytochrome P450s based on electrodes with immobilized substrates].

A new approach for the electrochemical reduction of cytochromes P450 (P450s, CYPs) with electrodes chemically modified with appropriate substrates of P450s ("reverse" electrodes) has been proposed. The method is based on the analysis of cyclic voltammograms, square wave voltammograms, amperograms and determination of such electrochemical characteristics as catalytic current and redox potential. The sensitivity of the proposed method is 0.

[Electrochemical reduction of cytochrome P450 as a way for construction of biosensors and bioreactors].

The present review describes the data on electrochemical reduction of cytochrome P450. Three generations of enzyme biosensors have been considered. The concept and potentialities of enzyme electrodes--transducers--as the main element on construction of electrochemical biosensors are described.

[Study of interaction of cytochrome P450 2B4 with riboflavin by fluorescence spectrometry].

Fluorescence quenching of riboflavin by cytochrome P450 2B4 was used to probe the ligand--enzyme binding interaction ((lambda ex = 385 nm, lambda em = 520 nm). Riboflavin is a component of a flavoprotein NADPH dependent cytochrome P450 reductase, an essential electron carrier during cytochrome P450 catalysis. Fluorescence titration measurements revealed that cytochrome P450 2B4 and riboflavin formed a complex with an apparent Kd = 8.

[Photoreduction of flavocytochrome P450 2B4].

It was shown that noncovalent complexes of riboflavins and cytochrome P450 2B4 (flavocytochrome P450 2B4) can be used for photoinduced intramolecular electron transfer between the isoalloxazine cycle of flavins and the cytochrome P450 2B4 heme. The measurement of the photocurrent generated by photoreduction of noncovalent flavocytochrome P450 2B4 was carried out. It was found that, in the presence of typical substrates for cytochromes P450, the cathode photocurrent generated by both riboflavin and a mixture of riboflavin with cytochrome P450 decreases.

[The use of alternative sources of electrons in mono-oxygenase reactions catalyzed by cytochrome P450. Physico-chemical methods as factors acting on enzymatic activity of proteins].

Influence of physico-chemical methods on catalytic activities of enzymes, (cytochrome P450 in particular), has been reviewed. Authors discussed the properties of semisynthetic flavohemoproteins based on cytochrome P450. With emphasis on recovery of alternative electron sources for redox enzymes.

[Peroxide-dependent oxidation of substrates of polysynthetic flavocytochrome 2B4].

Semisynthetic flavocytochromes, obtained by covalent binding of riboflavins with cytochrome P450 2B4, were able to catalyse H2O2-supported aniline p-hydroxylation, amidopyrine N-demethylation and p-nitroanisole O-dealkylation. Rates of these reactions were considerably higher than the rates of corresponding NAD(P)H-dependent reactions and comparable with H2O2-dependent reactions, catalysed by cytochrome P450. Kinetic parameters (Km and kcat) of hydrogen peroxide-supported oxidation of aniline, amidopyrine and p-nitroanisole in the presence of flavocytochrome 2B4 were determined.

[The interaction of organophosphorus amino acid analogs with cytochrome P-450 2B4].

Interaction between phosphorus amino acids analogs, 1-aminoalkylphosphonous and 1-aminoalkylthiophosphonic acids, and microsomes from the liver of phenobarbital-induced rabbits was studied. The phosphorus amino acids analogs cause type I and reverse type I spectral changes, respectively. A new reaction in the microsomal monooxygenase system was revealed.

[Inhibition of the angiotensin-converting enzyme from bovine kidney by organophosphorus analogs of amino acids].

Reactions of amino acid phosphoorganic derivatives with angiotensin-converting enzyme (dipeptidyl carboxypeptidase) were studied. Substitution of the amino acid carboxyl group by HS- or P(O) (OH)2-groups did not cause the enzyme considerable inhibition. The enzymatic activity was inhibited by 20-50% in presence of 1 X 10(-3) M Asp, Met and Cys phosphoorganic derivatives.