Appeal No. 1999-2141
Application No. 08/657,164
describes that in the pH range of 6-8, suitable buffers for ion exchange chromatography
may be selected from four possible buffers, including Tris [tris(hydroxymethyl) amino
methane]. The examiner indicates that given the isoelectric information for $-taipoxin
described in Fohlman, it would have been obvious to one of ordinary skill in the art to
employ the common Tris buffer at a pH range of around 7 to elute $-taipoxin purified
fraction. Answer, page 5.
The examiner relies on Tyler and Bougis for establishing that “HPLC affords a
convenient, high resolution method of separation by means of a single step.” Answer,
page 6. Bougis suggests that the isolation of toxins from venom is “consistently a thorny
problem in biochemistry”, and deals only with isolation of toxins from Elapidae snake
venoms of the genus Naja using reverse phase HPLC. See Bougis page 7235, column 1,
and 7236, column 2. Similarly, Tyler uses reverse phase HPLC to isolate textilotoxin from
Australian brown snake, consisting of five non-covalently linked subunits. Tyler suggests
that while textilotoxin shows some similarity with taipoxin, the toxins are “definitely not
identical”. Tyler, page 215.
The examiner concludes that it would have also been obvious that in following these
teachings, the subject matter as a whole would have been obvious, i.e., the separation of
beta taipoxin subunits and the separation of non-toxic and toxic parts, would have been
achieved by following HPLC techniques. The examiner further finds the “steps of adding a
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