Abstract: The invention provides methods of synthesizing peptides, involving the steps of providing a composition including a peptide fragment, wherein the peptide fragment has at least one amino acid residue and includes a base-sensitive, N-terminal protecting group; removing the base-sensitive, N-terminal protecting group from the peptide fragment using a deprotection reagent that includes a base, whereby an N-terminal functionality on the peptide fragment is deprotected; removing the base from the composition to provide a residual base content of more than 100 ppm; causing a reactive peptide fragment having a reactive C-terminus and a base-sensitive N-terminal protecting group to react with the deprotected N-terminal functionality of the peptide fragment under conditions such that the reactive peptide fragment is added to the peptide fragment; and optionally repeating the deprotection and coupling steps until a desired peptide is obtained.

Abstract: The present invention relates to methods of purifying proteins having surface active, electron-rich amino acids using an aqueous two phase system. The methods include the use of salts and inert hydrophobic molecules, such as polymers, to produce the aqueous two phase system and the use a polymer-chelator-metal complex to purify the target proteins.