ABSTRACT
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.
Subject(s)
Blood Substitutes/chemistry , Blood Substitutes/chemical synthesis , Hemoglobins/chemistry , Hemoglobins/chemical synthesis , Pyridoxal Phosphate/analogs & derivatives , Animals , Blood Substitutes/pharmacology , Dogs , Electrochemistry , Erythrocytes/chemistry , Erythrocytes/drug effects , Hemoglobins/pharmacology , Humans , Molecular Weight , Oxygen/blood , Oxygen/chemistry , Oxyhemoglobins/chemistry , Pyridoxal Phosphate/chemical synthesis , Pyridoxal Phosphate/chemistry , Pyridoxal Phosphate/pharmacology , RatsABSTRACT
Solutions of oligohemoglobins (OHb) with middle molecular mass 100 x 10(3) = 400 x 10(3), obtained after polycondensation of hemoglobin with glutaric aldehyde as well as oligohemoglobin modified with pyridoxal-5-phosphate, were studied in vivo and in vitro (plethoric administration, isovolemic metabolic substitution, hemorrhagic shock; at a dose of 0.5-1.8 g/kg of body mass; dogs, rabbits, rats). With increase of the OHb molecular mass period of its circulation in blood was elevated; blood plasma protected OHb from autooxidation; half-life of OHb was about 12-18 hrs in isovolemic metabolic substitution and in hemorrhagic shock and about 5 hrs--in plethoric administration. During circulation molecular mass selection of OHb occurred, where low molecular fraction decreased and high molecular fraction--accumulated; sign and value of human erythrocyte charge were similar both in OHb solutions with concentration up to 5% and in physiological solution.
Subject(s)
Hemoglobins/chemistry , Animals , Dogs , Erythrocytes/chemistry , Glutaral/chemistry , Humans , In Vitro Techniques , Molecular Weight , Oxidation-Reduction , Pyridoxal Phosphate/chemistry , Shock, Hemorrhagic/blood , SolutionsABSTRACT
Oligomeric hemoglobins were produced after polycondensation with glutaric aldehyde (OHb) as well as after modification with pyridoxal-5-phosphate (OHb-PLP). OHb exhibited high affinity to oxygen (P50 = 17 torr) as well as a decreased rate of the subunits cooperative interaction (n = 1.5-1.6); OHb-PLP possessed P50 = 27 torr, n = 2.2 (for pO2 greater than P50), Bore effect -0.4. The P50 pattern was not distinctly altered in presence of approximately 15% Met hemoglobin, while already 8% of the Met form affected the "n" parameter. Biological activity of OHb and OHb-PLP was studied.
