Native chemical ligation of unprotected solid phase or protected in the n-terminal cysteine peptide in aqueous solution.

The present invention provides methods, devices and kits assembled to synthesize peptides and proteins on a solid phase sequential ligation of three or more unprotected peptide segments using chemical linkage and moderate quimioselectivos in an aqueous solution. procedures is also provided to display the sequential ligation reactions using a solid phase mass spectrometry MALDI ionization type or electron spray on the reaction products.