Appeal No. 1997-3501
Application No. 08/253,232
Claim 24 is illustrative of the claims on appeal and reads as follows:
24. A process for the preparation of a pasteurized and purified von Willebrand
factor concentrate, which comprises:
a) preparing a solution selected from the group consisting of cryoprecipitate,
Cohn fraction I, a supernatant of a cell culture and an extract of a cell culture, said solution
having a pH of 5.5 to 7.3, and containing von Willebrand factor (vWF) as a complex with F
VIII:C, a carbohydrate at a concentration of 5-30% w/w, calcium ion, and amino acids;
b) treating said solution with an anion exchanger to which F VIII:C binds to
obtain a pasteurized von Willebrand factor concentrate free of F VIII:C;
c) treating said von Willebrand factor solution free of F VIII:C with 0.5 to 3 mol/l
glycine to precipitate proteins from said solution;
d) removing said protein precipitate from said solution to form a glycine
supernatant solution containing von Willebrand factor;
e) adding NaCl at a concentration of 2-15% w/v to said glycine supernatant
solution to precipitate von Willebrand factor; and
f) recovering precipitated von Willebrand factor.
The prior art references relied upon by the examiner in rejecting the
appealed claims are:
Kotitschke et al. (Kotitschke) 4,272,523 Jun. 9, 1981
Mitra et al. (Mitra) 4,543,210 Sep. 24, 1985
Mathews et al. (Mathews) 4,743,680 May 10, 1988
British Patent Application
Costello 2 079 292 Jan. 20, 1980
2
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