Appeal No. 2002-1479 Page 3
Application No. 08/794,042
Light et al., J. Protein Chem. 10:475(1991), disclosed what was later proven to
be an incorrect partial amino-terminal sequence for the catalytic subunit of bovine
enterokinase. To date, it has been impossible to obtain recombinantly produced
enterokinase activity and there continues to exist a need for such a product.” Id.,
page 2.
The specification discloses cloning of DNA encoding bovine enterokinase.
See pages 10-19. The specification also discloses expression of the enterokinase
light chain in recombinant host cells. See pages 20-24. Expression of the cloned
light chain in CHO host cells resulted in secretion of a 42 kD product into the
conditioned medium. See page 20.
Discussion
Claim 42 is directed to an active, recombinant enterokinase light chain,
free of heavy chain, comprising amino acids 564-798 of SEQ ID NO:2. The
examiner rejected the claim as anticipated by Light. As noted by the examiner,
Light teaches “purification of the catalytic subunit of bovine enterokinase.”
Examiner’s Answer, page 3. The examiner concluded that Light’s purified
enzyme meets all the limitations of claim 42, for the following reasons:
(1) “The catalytic subunit . . . appeared as a single component on SDS-
gel electrophoresis. . . . Therefore, the purified bovine catalytic subunit meets
the recited limitation of enterokinase light chain, free of enterokinase heavy
chain.” Examiner’s Answer, page 4.
(2) “Light et al[.] teach that the isolated light chain enterokinase was
enzymatically active . . . and thus meets the functional limitation of biologically
active in the claim.” Id.
(3) “While the claim is limited to a specific sequence, it is noted that the
claimed sequence was derived from cloning the bovine DNA. . . . Light et al[.]
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