Appeal No. 1996-0223
Application No. 07/931,563
and purification, i.e., isolation, of Factor IX, a vitamin K-dependent protein, by immunoaffinity
chromatography using an immobilized antibody which binds to Factor IX in its “non-stabilized
conformational” state (i.e., binds to Factor IX in citrated plasma) (col. 6, lines 9-66). However, as
argued by appellants to no avail, the Zimmerman antibody also binds to Factor IX in its active
“stabilized conformational” state because Zimmerman only identified “positive clones” as those in which
“the [hybridoma] supernatant substantially neutralized Factor IX clotting activity” (Zimmerman col. 3,
lines 45-46; brief, pages 6-7). In other words, the Zimmerman antibody binds to Factor IX
irrespective of whether or not the Factor IX is itself bound to a metal ion. The Zimmerman antibody is
not a conformation-specific antibody.
Secondly, while Zimmerman suggests that a calcium chloride containing buffer may be used to
elute purified Factor IX from the immunoaffinity column, it is stated to be “preferably at a concentration
of about 0.1 to 1.0 M” (col. 6, lines 61-65). As argued by appellants, this is elution by normal ionic
disruption using a strong salt, i.e., a high ionic concentration of calcium and chloride ions, not elution by
inducing any change in conformational state as recited in the claims (brief, pages 7-8). The skilled
artisan would have expected changes in conformational states of blood proteins to occur under normal
physiological conditions. For example, human adult blood serum normally contains 2.10 - 2.55 mM
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