Kinetics of the cyanate-hemoglobin reaction in whole blood

The kinetics of the cyanate-hemoglobin reaction in normal whole blood have been investigated. The mechanism was found to be second order, irreversible, bimolecular. The influence of the temperature, pH, Po2, and Pco2 on the reaction rate constant was examined. A temperature change from 37 degrees to 42 degrees C, resulted in a 50 percent increase in the rate constant. The rate constant increased in proportion to the pH decrease, and deoxygenated whole blood was carbamylated approximately twice as fast as oxygenated blood. Carbon dioxide pressures had no influence on rates of carbamylation when a constant pH was maintained. A maximum rate constant of 3.7 M-U min.-u was obtained with conditions which were compatible with the red blood cells. This knowledge of the reaction mechanism and the influence of important system parameters on the reaction rate constant may be applied to the development of an extracorporeal system for the treatment of sickle cell anemia.