Appeal No. 1997-3501
Application No. 08/253,232
In the case before us, it is clear that the field and scope of the prior art, protein
purification, remains unpredictable. As acknowledged by Harris at page 60, a universal
purification strategy for all proteins cannot be given since the materials available and the
requirements for each application differ. Harris, also, states that there is no substitute for
trial and error. Wang recognizes that many variables affect protein stabilization and
denaturation, including solvents, hydrophobic interactions, oxidation potential, temperature
and pH, to name a few. Thus, the purification and pasteurization procedures for Factor
VIII:C, provided in the cited references, would not necessarily provide one of ordinary skill
in the art with the purification procedures for vWF, a different protein having different
properties.
While Costello appears most relevant to the claimed method as it deals with
purification of vWF, it does not address specifically the pasteurization conditions for vWF,
and does not disclose the claimed purification process steps. The process of Costello
starts with a precipitate of solubilized cryoprecipitate by product formed in the production
of Factor VIII which includes vWF, and then solubilizes, precipitates, and resolubilizes vWF
to effect purification. In contrast, the claimed method isolates vWF from solution only after
having removed Factor VIII:C and other proteins and does not appear to require
precipitation and resolubilization of vWF.
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