Synthetic Peptide Purification via Solid-Phase Extraction with Gradient Elution: A Simple, Economical, Fast, and Efficient Methodology.

A methodology was implemented for purifying peptides in one chromatographic run via solid-phase extraction (SPE), reverse phase mode (RP), and gradient elution, obtaining high-purity products with good yields. Crude peptides were analyzed by reverse phase high performance liquid chromatography and a new mathematical model based on its retention time was developed in order to predict the percentage of organic modifier in which the peptide will elute in RP-SPE. This information was used for designing the elution program of each molecule.

Synergistic bactericide and antibiotic effects of dimeric, tetrameric, or palindromic peptides containing the RWQWR motif against Gram-positive and Gram-negative strains.

Dimeric and tetrameric peptides derived from LfcinB (20-25): RRWQWR, LfcinB (20-30): RRWQWRMKKLG, LfcinB (17-31): FKARRWQWRMKKLGA, or the palindromic sequence LfcinB (21-25): RWQWRWQWR were obtained by means of the SPPS-Fmoc/Bu methodology. The antibacterial activity of these molecules was evaluated against (ATCC 25922 and ATCC 11775), (ATCC 25923), (ATCC 29212), and (ATCC 27853). The dimer LfcinB (20-25): (RRWQWR)K-Ahx, the tetramer LfcinB (20-25): (RRWQWR)K-Ahx-C, and the palindromic sequence LfcinB (21-25) exhibited the highest antibacterial activity against the tested bacterial strains.