Appeal No. 1997-2517
Application No. 08/155,102
gonadotropin. The specification also discloses (page 2) that genomic and cDNA
clones for the a subunit were known in the art. Finally, the specification discloses
(page 11) that
Experiments using chemical derivatization in in vitro assays
indicate that amino acids at positions 88-92 (tyr-tyr-his-lys-ser) are
necessary for the signal transduction activity of the hormone.
Accordingly, deletion or alteration of one or more of these amino
acids by site-directed mutagenesis results in analogs which
continue to bind receptor but have reduced or negligible activity. All
four of the hormones sharing this alpha subunit can thus be
prepared as antagonists for the relevant hormone.
Discussion
Claim 14, the only independent claim on appeal, is directed to DNA
encoding a mutant human gonadotropin a subunit, where the mutation results in
an alteration or deletion of one or more of amino acids 88-92. The examiner
rejected all of the claims as obvious over the prior art.
Appellants acknowledge that “the recombinant means to construct the
DNA molecules of the invention were available in the art.” Appeal Brief, page 22.
Appellants also acknowledge that the prior art disclosed a subunit derivatives in
which the native a subunit was chemically modified to alter or delete one or more
of amino acids 88-92. Appeal Brief, pages 23-24. Appellants argue, however,
that the cited references would not have provided the requisite motivation to
make the claimed DNA, because the prior art would have led a skilled artisan to
expect that an a subunit mutated in amino acids 88-92, combined with a ß
subunit, would be unable to bind to its receptor. Appellants argue that a
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