Appeal No. 2005-1344 Page 5
Application No. 08/468,610
iii) the protein or peptide to be electrostatically charged at the pH where
the target protein or peptide is desorbed from the resin,
iv) desorption to occur by a change in the pH from the binding pH, and
v) about 50 percent or more of the target protein or peptide in an aqueous
medium binds to the resin when the aqueous medium has either a high or a low
ionic strength.
As discussed below, and emphasized by the underlining above, the intent
of a number of phrases and terms in appellants’ claims is unclear.
Ionizable ligand covalently attached to the matrix
According to appellants’ specification (page 15), “[t]he term ‘ionizable
ligand’ refers to a group covalently attached to the solid support matrix either
directly or through a spacer arm which group contains one or more functionalities
capable of being electrostatically charged at one pH and electrostatically
uncharged at another pH.” Appellants list a number of “[s]uitable ionizable
ligands,” which include carboxyl groups. See Id. As we understand it,
appellants’ Figures 8A through 8C illustrate an ionizable group covalently
attached to the solid support matrix either directly (Figures 8A4 and 8C 5) or
through a spacer arm (Figure 8B6).
4 “Figure 8A illustrates direct covalent attachment of the ligand to the solid support matrix….”
Specification, page 16.
5 “Figure 8C illustrates a resin having ionizable functionality or a mixture of ionizable
functionalities incorporated into the backbone of the solid support matrix.” Specification, page 17.
6 “Figure 8B illustrates covalent attachment of the ligand to the solid support matrix via a suitable
spacer arm incorporated into and comprising part of the ligand….” Specification, page 17.
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