Disclosed are a modified FIX (factor IX) polypeptide comprising a leucine, cysteine, aspartic acid, glutamic acid, histidine, lysine, asparagine, glutamine or tyrosine in position 338 pharmaceutical preparations containing said modified FIX polypeptide a nucleotide sequence coding for the modified FIX polypeptide and a method for producing the modified FIX polypeptide.