SIMULTANEOUS ANALYSIS OF BRADYKININ AND I TS METABOLITES BY CAPILLARYELECTROPHORESIS

We have developed and optimized the capillary electrophoretic procedur e for simultaneous analysis of bradykinin (BK) and its metabolites (C terminal-truncated peptides). When optimized, the capillary electropho rsis (CE) gave base-line resolution of BK and des-Arg9-BK, des-Phe8-Ar g9-BK, and des-Ser6-Pro7-Phe8-Arg9-BK within 10 min upon application. The peak areas were linearly related with the amount of peptides appli ed, and were highly reproducible (RSD<6%). The peptides were sufficien tly recovered (ca. 80%) from monkey blood plasma which had been immedi ately ultrafiltrated and applied to the CE. CE is superior to HPLC in that it requires less sample material, yields higher resolution, and i t can be readily equilibrated when one buffer is switched to another, although CE is somewhat less sensitive than HPLC inasmuch as an UV det ector is used. In addition, we optimized the rinse procedure for the p eptides, which was to rinse off the capillary using 500 mM phosphate b uffer pH 7.0. These procedures may enable the determination of the bio logical fate of BK, and benefit the exploration of the pathophysiologi cal significance of the peptide.