Ex parte HEIMBURGER et al. - Page 7

              Appeal No. 1997-3501                                                                                         
              Application No. 08/253,232                                                                                   

                     contaminants, and Mitra’s and Wang’s stabilizers will prevent denaturation of                         
                     a protein during heat treatment procedures.  It would have been obvious to                            
                     one with ordinary skill in the art at the time Applicants’ invention was made to                      
                     determine all operable and optimal parameters of a protein purification                               
                     procedure such as the buffer components and concentrations for all steps,                             
                     and the type and concentration of precipitating agents and the types of                               
                     purification steps as shown by Harris, because it is desirable to have a                              
                     procedure that will enable the protein to be purified to the greatest extent                          
                     with as few as contaminants as possible, and it is routine in the art to do so.                       
                     Austen describes the chromatographic separation of Factor VIII complexed with                         
              ristocetin, i.e., von Willebrand factor, on aminohexyl sepharose.  After binding of the                      
              complex which includes the vWF, to aminohexyl sepharose, the ionic strength is gradually                     
              increased with sodium chloride, successively releasing ristocetin from Factor VIII, to allow                 
              purification of Factor VIII.  Austen, page 672.  The examiner acknowledges that Austen                       
              does not disclose components of the claimed chromatography buffers, does not teach                           
              precipitation steps in a process for the isolation of vWF, and does not teach pasteurization                 
              of vWF, or the conditions for pasteurization.  Examiner’s Answer,                                            
              page 4.                                                                                                      
                     The examiner relies upon Mathews for the disclosure that blood proteins, such as                      
              Factor VIII:C, may be purified by anion exchange chromatography in the presence of a                         
              sugar,  sugar alcohol, amino acids and salt thereof, as well as the use of calcium chloride                  


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