Near-Infrared Multispectral Imaging Technique for Visualizing Sequences of Di- and Tripeptides Synthesized by Solid Phase Combinatorial Method

A new method based on the near-infrared (NIR) multispectral imaging technique has been developed for the noninvasive and nondestructive determination of the identity and sequences of amino acid residues in di- and tripeptides. The di- and tripeptides were synthesized on polymer beads (i.e., Rink) using the solid phase peptide synthetic method. The developed method is capable of determining the identity of sequences of the peptides (with and without the Fmoc protecting group) directly on the polymer beads. It can distinguish not only dipeptides from tri-peptides but also peptides with very similar structures (e.g., Rink-Gly-Ala-Ala, Rink-Gly-Ala-Phe, Rink-Gly-Ala-Leu, Rink-Gly-Ala-Val, and Rink-Gly-Ala-Met). More importantly, it is capable of distinguishing peptides with the same amino acid residues but different sequences (e.g., Rink-Gly-Leu-Val from Rink-Gly-Val-Leu).