Interaction of a Serum Inhibitor of C'I-Esterase with Intermediate Complexes of the Immune Haemolytic System II. KINETICS AND MECHANISM OF THE INTERACTION.

The kinetics of the reaction between C' I-esterase inhibitor and an intermediate complex of sensitized sheep erythrocytes and human complement are described. The rate of reaction was directly proportional to the concentrations of both inhibitor and intermediate complex, but was insensitive to changes in pH over the range 7.4 - 8.7 and in ionic strength from 0.15 - 0.24. The rate of reaction was accelerated b an increase in temperature over the range 22° - 37°. The experimental evidence was consistent with a mechanism picturing the reaction of C' I-esterase inhibitor with C' I-esterase bound to the intermediate complex. A theoretical treatment is described from which values for various kinetic and thermodynamic quantities may be calculated. [ABSTRACT FROM AUTHOR]