Appeal No. 2005-1344 Page 8
Application No. 08/468,610
pH 5-9 and electrostatic charge
During the November 15, 2005 Oral Hearing, appellants’ representative
was questioned a number of times as to the intended meaning of the phrase pH
5-9 as it is used in the context of the claimed invention. According to appellants’
representative, the phrase “pH of 5 to 9” refers to a pH range wherein throughout
the entire pH range from 5 through 9, the target protein/peptide is bound and
remains bound to the resin. This statement appears to be consistent with
appellants’ summary of the claimed invention, wherein appellants state (Brief,
page 3),
[r]esins of the present invention are selected such that the ionizable
ligand is uncharged at a pH where the target protein or peptide is
bound to the resin and electrostatically charged[ ]8 at a pH where the
target protein or peptide is desorbed from the resin. … Resins of
the present invention … are uncharged in a pH range of 5-9. See
p. 29, lns 24-28.
The examiner appears to agree with this interpretation of the claimed invention.
See Answer, page 5, “[a] complex … is claimed wherein the complex is formed at
a pH value of between 5-9, where the resin is uncharged, and the target protein
is bound to the resin by hydrophobic interactions.”
This construction of the claimed invention, however, does not appear to be
supported by appellants’ specification. At page 29, lines 24-28, appellants’
specification discloses “the ionizable ligands attached to the solid support matrix
should provide resins which begin to titrate (become electrostatically charged) in
a pH range of from about 5 to 9 and more preferably from about 5.5 to about
8 According to appellants’ specification (page 18), the term “electrostatically uncharged” “means
that less than 5% of the ionizable functionalities on the resin are charged at the pH of target
protein binding.”
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