Fig. 1.

The time course of the reaction of FITC with the h2E2 mAb at 22°C in borate buffer, pH=8.0. Aliquots were taken and the excess FITC reagent was removed, and the buffer exchanged to PBS by size exclusion chromatography at the times indicated, and the degree of labeling (mol FITC/mol mAb) was determined spectroscopically as described in Methods. Three independent experiments were performed, and the means and standard deviations for each time point are shown in the figure. The curve shown is a power function fit to the data means at each time point.