The article analyzes the role of hydrogen bonds and supramolecular structures in enzyme catalysis and model systems. Hydrogen bonds play a crucial role in many enzymatic reactions. However, scientists have only recently attempted to harness the power of hydrogen bonds in homogeneous catalytic systems. One of the newest directions is associated with attempts to control the properties of catalysts by influencing the “second coordination sphere” of metal complexes. The role H-bonding, and the building of stable supramolecular nanostructures due to intermolecular H-bonds, based on catalytic active heteroligand iron (Fe) or nickel (Ni) complexes formed during hydrocarbon oxidations were assessed via the AFM (Atomic-force microscopy) method, which was proposed and applied by authors of this manuscript. Th is article also discusses the roles of hydrogen bonds and supramolecular structures in oxidation reactions catalyzed by heteroligand Ni and Fe complexes, which are not only effective homogeneous catalysts but also structural and functional models of Oxygenases.

For the first time AFM (atomic-force microscopy) was used to record significant changes in the geometric parameters of the image of erythrocytes in vitro under conditions of glycolytic starvation (ATP (Adenosine triphosphate) deficiency). The difference in the action of antioxidants, phenosan K, and Ihfan-10 on erythrocytes that we detected with AFM seems to be mainly due to their difference in hydrophobicity. We used the AFM method to research the self-organization of the components of the active center of P450 (Porphyrin-450) metalloenzymes that are part of a class of hemoproteins with functions of affinity to molecular oxygen O₂. Stable supramolecular nanostructures in the form of triangular prisms based on the iron porphyrin complex with amino acids due to self-assembly involving intermolecular hydrogen bonds were received. A possible scheme for the formation of such structures is proposed.

It is known that the presence of redox-inactive metals in the active center of an enzyme has a significant effect on its activity. In this regard and for other reasons, the effect of redox-inactive metals on redox processes, such as electron transfer, oxygen and hydrogen atom transfer, as well as the breaking and formation of O–O bonds in reactions catalyzed by transition metals, has been widely studied. Many questions about the role of redox-inactive metals in the mechanisms of these reactions remain open. In this paper, the mechanism of catalysis by bi- and triple hetero-binuclear heteroligand complexes including Ni and redox-inactive alkali metals ((A) {Ni(acac)₂∙L²} and (B) {Ni(acac)₂∙L²∙PhOH} (L² = MSt (M = Li, Na, or K)) in the process of the selective oxidation of ethylbenzene by molecular oxygen into α-phenyl ethyl hydroperoxide is considered. The activity of A and B complexes towards O₂, ROOH, and RO₂^• radicals was studied. Based on kinetic data, we suggest that the high catalytic efficiency of B triple complexes in oxidation processes may be associated with the role of outer-sphere regulatory interactions, with the formation of stable supramolecular structures due to intermolecular H bonds. This assumption was confirmed using the AFM method. Prospects for studying catalysis by complexes ({Ni(acac)₂∙L²} and {Ni(acac)₂∙L²∙PhOH}) that are models of NiARD (Ni-Acyreductone dioxygenase) are discussed.

The role of ligands in the regulation of the catalytic activity of Ni-complexes (Ni(acac)₂) in green process-selective ethylbenzene oxidation with O₂ into α-phenyl ethyl hydroperoxide is considered in this article. The dual function of phenol (PhOH) included in the coordination sphere of the nickel complex as an antioxidant or catalyst depends on the ligand environment of the metal. The role of intermolecular H-bonds and supramolecular structures (AFM method) in the mechanisms of selective catalysis by nickel complexes in chemical and biological oxidation reactions is analyzed.

In this paper, using fluorescence and confocal microscopy, we study the content of the flavin adenine nucleotide (FAD) cofactor and enzymatic NAD(P)H-oxidase complexes (with fluorophores Annexin V‑ FITC, 7-AAD (7-aminoactinomycin D), EtBr) under conditions of apoptosis caused by sodium anphen with hydrogen peroxide in healthy mouse splenocytes and Lewis carcinoma tumor cells. The use of fluorescence microscopy allows observing and quantifying the apoptotic effect of sodium anphen and hydrogen peroxide, and it also allows visualizing the metabolic changes in the cell, including the increased fluorescence of FAD in tumor cells and NAD(P)H-oxidase complexes in splenocytes. The data obtained indicate the possibility of using sodium anphen in combination with hydrogen peroxide as an antitumor drug acting on certain types of cells.

Currently, poly- and monophenol antioxidants should be considered not only as inhibitors that interact with free radicals, but also take into account that they are biologically active substances that affect specific targets in cells and can induce the activity of certain genes or stimulate various signaling pathways. The phenols can directly influence different points of the apoptotic process, and/or the expression of regulatory proteins. In our present study the effect of two antioxidants, sterically hindered monophenols sodium anphene (ANa) and potassium phenosan (PhK), on cell apoptosis of splenocytes was studied by fluorescence and confocal microscopy. PhK has already been introduced into medical practice in the Russian Federation because it proved effective as an anticonvulsant and was useful in treating neonatal hypoxia. The study of ANa continues; it may be a promising anticancer drug for some types of tumors. The fluorescent and confocal microscopy methods demonstrate that ANa in combination with H₂O₂ enhances apoptosis in suspension of Lewis carcinoma cells and to a lesser extent in splenocyte culture. We also discovered that autofluorescence of FAD and immunofluorescence of NADPH enzymatic complexes (with the AV-FITC fluorophore) in splenocytes of normal cells increases symbatically. The autofluorescence of FAD in splenocytes of Lewis carcinoma cells significantly exceeded that of splenocytes of healthy animals. The exact distinctive result was obtained when using potassium phenozan. It turned out that PhK prevents the development of apoptosis in mouse splenocyte cell culture (F1(CBA×C57B)). The combined use of ANa and PhK had no effect on splenocyte apoptosis. We show that fluorescence and confocal microscopy allow observing and quantifying the apoptotic effect of ANa and hydrogen peroxide, and make it possible to visualize metabolic changes in the cell, increased FAD fluorescence in tumor cells and NADPH -oxidase complexes in splenocytes. The data obtained indicate the possibility of using ANa in combination with hydrogen peroxide as an antitumor drug acting on certain types of cells. The different effects of sterically hindered monophenols ANa and PhK on the level of the anti-apoptotic protein Bcl-2 in the cell were established. ANa acts to lower Bcl-2 levels, signaling apoptosis, while PhK prevents the development of apoptosis and induces repair processes.