Synthesis, Purification and Surface Activities of the Human Pulmonary Surfactant Protein-C (SP-C) Analogue, SP-CL16 (6—28)

We previously reported that a human analogue of pulmonary surfactant protein-C (SP-C), SP-CL16 (6—28), with 23 residues (Fig. 1) was the most active analogue in a reconstituted lipid mixture and had the shortest chain among the poly-leucine-analogues examined. In the present study, we examined a new method of preparing this analogue, that is, stepwise solid-phase synthesis employing the Fmoc method followed by centrifugal partition chromatography (CPC) using an n-hexane/CH3OH/H2O/trifluoroacetic acid (TFA) (1000:1000:1:2, v/v) solvent system according to the descending method. The synthetic peptides were identified by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry in search of activity to improve the in vitro surface activity of a ternary lipid mixture composed of dipalmitoylphosphatidylcholine, egg-phosphatidylglycerol and palmitic acid (75:25:10, w/w) in a Langmuir-Wilhelmy surface balance. SP-CL16 (6—28) seemed comparable in surface activity with Surfacten® (Surfactant-TA), a modified surfactant preparation which has been used for the treatment of respiratory distress syndrome.