Abstract: An improved process for purifying a polypeptide using a packing material for reversed phase high performance liquid chromatography is provided. A process for purifying a polypeptide characterized in that an aqueous solution containing polypeptide obtained by pre-treating a polypeptide produced by a wide variety of cells to a predetermined state is adjusted to a specific pH value, to remove impurities, and is then treated with a packing material for reversed phase high performance liquid chromatography.

Abstract: A C-terminal amidating enzyme composition is disclosed having the ability to amidate the C-terminus of peptides with a C-terminal glycine. The C-terminal amidating enzyme is characterized by having a stable pH range of 5 to 9, metal ions and L-ascorbic acid as cofactors, two active fractions at molecular weights of about 50,000 and about 100,000 as determined from gel filtration, isoelectric points of about 4.5 pH for the active fraction having a molecular weight of about 50,000 and about 6.7 pH for the active fraction having a molecular weight of about 100,000 according to isoelectric point chromatography, and is activated by addition of catalase.