Patent 7183391 was granted and assigned to ZymoGenetics on February, 2007 by the United States Patent and Trademark Office.
We claim the proteinase inhibitors comprising a Kunitz domain, wherein the Kunitz domain comprises amino acid residues 57–107 of SEQ ID NO: 2. We also claim a fusion protein comprising said Kunitz domain. In addition, we claim a method of inhibiting protease degradation or protease activity in a composition which contains plasma proteins and proteases. The proteinase inhibitors is used as components of cell culture media in cell culture process, and as inhibitors of protease-mediated degradation of plasma proteins in protein purification.