REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND CAPILLARY ELECTROPHORESIS IN THE STABILITY STUDY OF THE NEUROPEPTIDE GROWTH-FACTOR ANTAGONIST [ARG(6),D-TRP(7,9),MEPHE(8)]-SUBSTANCE P(6-11) - A COMPARATIVE-STUDY

Reversed-phase high-performance liquid chromatography and capillary zo ne electrophoresis are widely used in protein and peptide analysis. De gradation of the basic peptide [Arg(6), D-Trp(7,9), MePhe(8)]-substanc e P (6-11) (antagonist G) was monitored with reversed-phase high-perfo rmance liquid chromatography, free capillary zone electrophoresis, and capillary zone electrophoresis with a capillary cationic coating. Cap illary zone electrophoresis with a dynamically coated capillary provid ed better separation between antagonist G and its degradation products (formed at pH/H 13) than high-performance liquid chromatography and f ree zone capillary electrophoresis. Rate constants of the alkaline deg radation of antagonist G measured with reversed-phase high-performance liquid chromatography and capillary zone electrophoresis with a dynam ic coated capillary wall are similar whereas the values measured with free zone capillary electrophoresis are lower. Rate constants for the degradation of antagonist G in acidic media are comparable for the thr ee techniques. It is concluded that capillary zone electrophoresis usi ng a dynamic coating with Fluorad is the most suited of the above-ment ioned techniques in analyzing antagonist G and its degradation product s. (C) 1994 Academic Press, Inc.