Synthetic Peptide Purification in The Multi-Coil Countercurrent Chromatograph

Separations of hydrophobic synthetic peptides in counter-current chromatography

Synthetic peptides with many aromatic, aliphatic and especially acidic amino acid residues are not very soluble and require strong solvents for useful partitioning. A chloroform-methanol-acidic solvent system fractionates neutral and basically charged 26-mers to provide high yields. An insoluble 15-mer with 5 Trp residues and 60% overall hydrophobic amino acid content was purified in pyridine-acetic acid and in another basic t-butyl methyl ether-n-butanol-acetonitrile solvent system with high recovery. Two instruments were used, the eccentric-multi-layer hybrid coil planet centrifuge and the new spiral disk planet centrifuge that were able to retain the stationary phase of these solvent systems, some of which have low interfacial tension.

Separation and purification of peptides by high-speed counter-current chromatography

Preparative separations of peptides have been accomplished using high-speed counter-current chromatography. This has been made possible by the use of a particular solvent system that does not exhibit solvent carryover at high speed flow and centrifugation conditions. The solvent system composed of tert.-butyl methyl ether, n-butanol, acetonitrile and aqueous trifluoroacetic acid which can be adjusted in volume ratios and percent acid is employed in two instruments for counter-current chromatography. The cross-axis coil planet centrifuge was used for separation of various dipeptides. Superior resolution was obtained with the multi-layer coil planet centrifuge in the separation of six dipeptides and in the preparative purification of two synthetic peptides.