Appeal No. 1999-2231
Application No. 08/278,774
propeptide or replacing the proteolytic cleavage site of an existing propeptide
with a non-native site.” In addition, appellants argue (Brief, page 5) that:
[o]ne would have to turn Carter on its head to fuse a collagen
propeptide to a collagen protein and then call it an “affinity handle”.
The whole point of Carter and affinity handles is to take a protein
that doesn’t provide a good binding target and stick a convenient
tag on it. If collagen propeptides provided affinity tags, there would
be no point in making a fusion protein – a suitable handle is already
there.
In response, the examiner argues (Answer, page 4) that:
[a]pplicants do not argue that putting two (or three) well
known sequences together with a “non-natural site-specific
proteolytic agent recognition site” between them would not
have been obvious over the prior art but rather [they] argue
that there would be no motivation to do so. As stated in the
final rejection this construct could be made to purify the
collagen with an afifnity handle. This is taught in Carter, first
paragraph. For instance, an antibody could be made to
particular procollagen, the construct of the instant claims
could be put on an affinity column containing this antibody
bound to a solid matrix, the contaminating proteins washed
out and then the site-specific cleavage means could be
employed to cleave the collagen molecule, thereby
facilitating purification. This same procedure could also
have been done batch-wise, not using a column.
The examiner further argues (Answer, bridging paragraph, pages 5-6) that:
[o]ne could make a cleavage site that could be readily and easily
cleaved using a site-specific cleavage means instead of using the
cleavage means used in the processing of natural collagen, [sic].
This process[ing of natural collagen] uses enzymes thought to be
expressed only in cells that naturally produce collagen. In addition,
the use of the construct in a purification scheme involving solubility
discussed supra has not been addressed by applicants.
As set forth in In re Soderquist, 326 F.2d 1016, 1018, 140 USPQ
387, 389 (CCPA 1964)
It is not necessary in a combination rejection that the structure of
one reference be substituted bodily in that of the reference with
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