R. N. Mishaeva

Reactions of glutaraldehyde with dipolar ions of amino acids and proteins

The review covers studies of the reactions of glutaraldehyde with dipolar ions of amino acids and proteins in neutral aqueous solutions. The formation of imines and the accompanying aldol condensation of glutaraldehyde are acid-catalyzed reactions.

Modelling of gas transport function of erythrocytes in haemoglobin sorption immobilization

Colloid-disperse systems based on haemoglobin sorption immobilization in reticular polyelectrolytes are proposed and investigated. The efficiency of oxygen transport of these systems is much higher than that of native haemoglobin and is comparable with the efficacy of gas transport of erythrocytes. This is believed to be due to highly selective sorption immobilization of haemoglobin in microdisperse forms of permeable carboxylic reticular polyelectrolytes. Microparticles exhibit high local concentration of haemoglobin, the protein mass being by one order of magnitude higher than that of the polymer carrier.

Synthesis, physico-chemical and biological properties of crosslinked modified hemoglobin

Polymer aspects of polycondensation of pyridoxylated hemoglobin with glutaraldehyde have been considered. On the basis of the investigation of reaction kinetics, the mechanism of chemical crosslinking of hemoglobin molecules into oligohemoglobin is proposed. Owing to the statistical character of the reaction, the resulting macromolecules are polydisperse with respect to the degree of modification of hemoglobin amino groups, and size of oligohemoglobin molecules. The formation of hemoglobin oligomers was studied by varying the following reaction conditions: pH, the components ratio, and their concentrations. It is shown that the net electric charge of the oligohemoglobin molecule depends on the terminating agents. However, these agents have no effect on the electrophoretic mobility of erythrocytes in oligohemoglobin solutions. The efficiency of oxygen transport of these solutions is close to that of human blood erythrocytes. Oligohemoglobin circulation in the blood of animals after intravenous infusion leads to rapid removal of low molecular weight fractions from blood and to the accumulation of high molecular weight fractions in plasma. The period of half-release of oligohemoglobin from the organism is 14-16 h.

Modification of a catalase by glutaraldehyde

Polycondensation of a catalase (EC 1.11.1.6) with glutaraldehyde in order to stabilize the quaternary structure of an enzyme, maintain its activity, and protect it from thermal denaturation was studied. Synthesis showed a superequivalent utilization of the aldehyde groups relative to the catalase amine groups, as a result of the formation of glutaraldehyde oligomers linked to the enzyme.Polycondensation of a catalase (EC 1.11.1.6) with glutaraldehyde in order to stabilize the quaternary structure of an enzyme, maintain its activity, and protect it from thermal denaturation was studied. Synthesis showed a superequivalent utilization of the aldehyde groups relative to the catalase amine groups, as a result of the formation of glutaraldehyde oligomers linked to the enzyme.

Oligomerization of Bifunctional Aldehyde in Reactions with Bipolar Ions

Formation of glutaraldehyde oligomers (tri- and pentamers) in reaction of glutaraldehyde with bipolar ions (monoaminoacetic, α-aminoglutaric, and α,ε-diaminocaproic acids and glutatione tripeptide) was studied.

Biologically active polymer systems based on hemoglobin

Development of the scientific principles involved in the creation of soluble macromolecular modifications of the native protein, hemoglobin, is surveyed. The main goal of the research is practical application of the results to develop blood substitutes with oxygen-transport function for treatment of massive blood loss. Models of red blood cells, which represent corpuscular polymer systems (microcapsules, liposomes, microdispersions) are considered.

Association-dissociation of molecules of hemoglobin and polymeric hemoglobin in solutions

The process of association-dissociation of hemoglobin molecules into dimers of its subunits in water and water-saline solutions is studied by the method of gel-penetrating chromatography and ultrafiltration. The quantitative assessment of stabilization of quaternary structure of hemoglobin in chemically bound polymer derivative in comparison with native peptide on the basis of building differential concentration curves is conducted for the first time. By the method of atomic-force spectroscopy, the morphology of nanoparticles of hemoglobin and its modified polymeric derivative is studied.

Sorption purification of concentrated hemoglobin solutions

A procedure was developed for purification of concentrated hemoglobin solutions from hemolyzate of human erythrocytes to remove soluble cellular impurities using a frontal chromatographic process on an anion exchanger under conditions of selective absorption of impurities and the absence of sorption of the target product, hemoglobin.

The Use of Polycondensed Hemoglobin as the Basis of a Blood Substitute Capable of Transporting Oxygen

† Development of blood substitutes that fulfil the vitally important respiratory function of the blood is a topical problem of medicine. The therapy of mass bleeding in surgery and saving of life in extreme situations (accidents, disasters, etc.) depends on its solution. To date, the only source of blood for treatment of heavy bleeding is donor blood or concentrated red cells (a component of blood). The use of donor blood entails some problems: donor blood is often lacking, the patient may be infected with a viral disease, the storage life of donor blood is short (five to seven days), a test for compatibility with the patient’s blood is necessary, and there is always the risk of unfavorable transfusion responses and complications. Therefore, development of blood substitutes that not only replenish the blood volume, electrolyte composition, and plasma osmotic pressure, but also fulfil the main gas-transporting function of the blood, which is oxygen supply to tissues, is an urgent problem. Development of blood substitutes transporting oxygen progresses along two main lines: the use of a mixture of low-molecular-weight perfluororganic compounds as transporters and chemical modification of hemoglobin (Hb), a natural protein reversibly binding oxygen. The latter approach is currently used by many research groups all over the world, and the preparations developed are at different stages of clinical trial [1]. Modified Hb is subjected to biodegradation in the patient’s body and is utilized through natural pathways. It has no group specificity characteristic of the blood and may be administered to any patient, it may be stored for a long time in the form of lyophilized powder without the loss of its functional properties, and it does not carry infectious agents. The main tasks involved in developing Hb-based blood substitutes are restoration of the decreased gas-transporting function (because of the loss of the oxygenation effector upon the release of Hb from erythrocytes) and an increase of the size of the Hb macromolecule (to avoid an irreversible lesion of

MICRODISPERSE FORM OF IMMOBILIZED HEMOGLOBIN MODELLING THE ERYTHROCYTES

Disperse systems based on hemoglobin sorption immobilization in reticular carboxylic polyelectrolytes are proposed as model of erythrocytes. The efficiency of oxygen transport of these systems is much higher than that of native hemoglobin and is comparable with the gas transport of erythrocytes. This is believed to be due to highly selective sorption of hemoglobin in microdisperse forms of permeable polyelectrolytes. Microparticles of immobilized hemoglobin exhibit high local concentration of hemoglobin: the protein mass being one order of magnitude than that of polymer-carrier. Besides, it is presumed that structure of the carboxylic polyelectrolyte matrix is a polymer analog of 2,3-diphosphoglycerate. Microdispersion of immobilized hemoglobin exhibits a aggregative resistance and have identity of surface charge with erythrocytes. Studies in vivo have revealed biocompatibility of immobilized hemoglobin.