Patent ID: 7666582

Claim:
A method of generating Fc or Fab fragments of IgG comprising: (i) contacting IgG with: a) polypeptide having the sequence of SEQ ID NO: 1, or b) a polypeptide having the sequence of SEQ ID NO: 1 except for 1, 2 or 3 conservative substitutions, wherein said polypeptide (a) and said polypeptide (b) have a cysteine residue at the position corresponding to position 65 of SEQ ID NO:1, position 65 of SEQ ID NO:1 corresponding to position 94 of SEQ ID NO:2, wherein IgG is contacted with said polypeptide (a) or said polypeptide (b) under conditions that permit the IgG specific cysteine protease activity of said polypeptide (a) or said polypeptide (b); (ii) thereby generating said fragments of IgG; and (iii) isolating the fragments of IgG obtained, or analysing the starting materials or reaction products to determine whether the desired product is present.