HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC PURIFICATION OF EXTREMELY HYDROPHOBIC PEPTIDES - TRANSMEMBRANE SEGMENTS

Transmembrane peptides of integral membrane proteins often exhibit ext remely high hydrophobicity. Therefore, the solubility of such peptides in solvents commonly used in HPLC is usually very low and the interac tion with generally applied stationary phases such as silica gel or C- 18 reversed phases appears to be extremely strong, which makes the cha racterization and purification of these peptides difficult. The analyt ical characterization and preparative separation of the synthesized M1 transmembrane sequence of the inhibitory glycine receptor M(r) 48000 subunit and some of its fragments is shown. M1 and its larger fragment s could be dissolved in a dichloromethane-hexafluoro-2-propanol mixtur e containing a trace amount of pyridine for their separation on a C-4 phase by employing linear two-component gradients of formic acid-2-pro panol and formic acid-water with ratios up to 4:1 (v/v). Conditions to avoid formylation of the peptides are indicated.