Kinetic analysis of calcium binding to concanavalin A

The kinetics of calcium binding to concanavalin A was studied utilizing ultraviolet difference spectral measurements. The results show that calcium binds to the lectin in a biphasic process: a rapid and reversible phase, followed by a relaxation phase with a kobs of 0.012 sec-1. Kinetic measurements were used to calculate the association constant, Ka, for calcium binding to concanavalin A of 2.7 x 10(4) M-1, in reasonable agreement with values obtained by equilibrium methods.