Proteinase inhibitors comprising a Kunitz domain are disclosed. The Kunitz
domain comprises a motif of amino acid residues as shown in SEQ ID NO:4, and the
sequence of the Kunitz domain is shown in residues 57 through 107 of SEQ ID NO:2.
The polypeptide also includes an N-terminal collagen domain in which a von Willebrand
domain resides, and is shown in SEQ ID NO: 5. Also disclosed are methods for making
the proteinase inhibitors, and expression vectors and cultured cells that are useful
within the methods. The proteinase inhibitors may be used as components of cell
culture media, in protein purification, and as inhibitors of protease degradation
of plasma proteins.
