A method of sequentially removing one or more N-terminal amino acid residues from an analog of a eucaryotic polypeptide synthesized in a foreign host, comprises contacting the eucaryotic polypeptide analog with aminopeptidase under suitable conditions permitting sequential removal of N-terminal amino acid residues, where the polypeptide analog contains amino acid residue or sequence of residues which blocks the action of an aminopeptidase located at a position other than the N-terminal end of the polypeptide analog. A specific embodiment of the invention concerns removing both an N-terminal methionine residue and its adjacent Leucine residue from a growth hormone analog produced in bacteria by contacting the growth hormone analog with Aeromonas aminopeptidase under suitable conditions permitting removal of the N-terminal methionine and Leucine residues. The invention also concerns eucaryotic polypeptide analogs produced in accordance with the methods of the invention.