Appeal No. 2004-2138 Page 11
Application No. 08/765,324
have been maintained. The fact that Lee removed the reducing agent from the
apolipoprotein preparation by dialyzing against distilled water is immaterial because the
apolipoprotein had been modified by carboxymethylation after it was reduced. Lundblad
discusses carboxymethylation of proteins.3 See, e.g., Lundblad’s Figure 2: treatment of
a protein with a reducing agent like dithiothreitol breaks the disulfide bonds that
normally exist between certain cysteine residues; thus, each –S—S– bond becomes
two –SH groups (the starting point of the reaction in Lundblad’s figure). Each –SH
group can then by carboxymethylated, converting it to an –S–CH2–COOH moiety.
Lundblad states that blocking the sulfhydryl (–SH) groups by, e.g., alkylation
prevents them from reoxidizing to re-form disulfide bonds. See page 95. Thus,
carboxymethylation prevents the protein from resuming its original, oxidized state; after
carboxymethylation, the original –S—S– bond cannot reform even if the reducing agent
is removed.
For this reason, the fact that Lee removed the reducing agent from reduced and
carboxymethylated Apo B does not distinguish the method disclosed by Lee from the
one claimed by Appellants. Both processes involve immunizing an animal with reduced,
carboxymethylated, solubilized, and purified apolipoprotein. Lee therefore anticipates
claims 48, 50, and 51; combined with Goding, it would have made obvious claim 49.
Summary
We conclude that the specification adequately describes the claimed process,
that Lee also describes the process of claims 48, 50, and 51, and that, combined with
3 Lundblad et al., Chemical Reagents for Protein Modification, Volume I, pp. 55-60 and 95-98, CRC Press
(1984). We cite Lundblad only as evidence of how Lee would have been understood by those skilled in
the art. Lundblad’s disclosure is not necessary to reach any limitation of the claims on appeal.
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