APPLICATION OF CAPILLARY AND FREE-FLOW ZONE ELECTROPHORESIS AND ISOTACHOPHORESIS TO THE ANALYSIS AND PREPARATION OF THE SYNTHETIC TETRAPEPTIDE FRAGMENT OF GROWTH HORMONE-RELEASING PEPTIDE

The use of high-performance electromigration separation methods, capil lary zone electrophoresis (CZE) and capillary isotachophoresis (CITP) and continuous free-flow arrangements of these two separation principl es, free-flow zone electrophoresis (FFZE) and free-flow isotachophores is (FFITP), was investigated in the analysis and purification of the s ynthetic C-terminal tetrapeptide fragment (H2N-Ala-Trp-D-Phe-Lys.NH2) of the growth hormone-releasing peptide. CZE and CITP were used for mi croanalysis of peptide preparations after different steps of their pur ification. The homogeneity of the peptide preparations, including frac tions of preparative separations, was quantified by relative zone leng th (CITP) and/or relative peak height (CZE). In addition, the data obt ained by CZE and CITP (electrophoretic and electroosmotic flow migrati on velocities) were utilized for conversion of micro-scale capillary s eparations (nano- to picomole level) into the preparative separations realized by FFZE acid FFITP with a capacity from tens to hundreds of m illigrams per hour.