Appeal No. 2005-1383
Application No. 09/364,847
lines 16-18).” Id. The examiner states that Peoples does “not teach a fusion of
enzymes catalyzing successive enzymatic reactions [emphasis added].” To that end,
the examiner relies on the teachings of Bülow that the (i) “preparation of a bifunctional
enzyme can be accomplished by joining the genes of two enzymes by removing the
translational stop signal at the 3’-end of the first gene and ligating the ATG-start codon
of the second gene in-frame with the first gene”; (ii) “the enzyme selected to be at the
N-terminal end [of a bifunctional enzyme] is arbitrary and that the native tertiary
structure of the fused enzymes remains almost intact”; (iii) “if the entire primary
sequences of the [] native enzymes are maintained in [a] fusion, the enzymes usually
retain most of their native specific activities despite being fused together;” and
(iv) “a linker peptide of two to ten amino acids separating the fused native enzymes
[of a bifunctional enzyme] is optimal.” Id., p. 8.
The examiner concludes that
. . . it would have been obvious to one of ordinary skill in the art to
combine the teachings of Peoples [] and Bulow [] for a beta-ketothiolase
and acetoacetyl-CoA reductase or acetoacetyl-CoA reductase and PHB
polymerase fusion protein having a linker of between two and ten amino
acids expressed in E. coli or a plant. One would have been motivated to
make a beta-ketothiolase and acetoacetyl-CoA reductase or acetoacetyl-
CoA reductase and PHB polymerase fusion protein having a linker of
between two and ten amino acids for expression in E. coli or a plant
because of the teachings of Peoples [] who teach PHB is a commercially
useful biopolymer that can be expressed in bacteria or plants as described
above and Bulow [] who teach the advantages of fusion proteins,
particularly those catalyzing sequential enzymatic reactions and that a
linker of two to ten amino acids separating the native enzymes is optimal
as described above [Answer, pp. 8-9].
In response, the appellants argue that Peoples “teaches the construction of
polymerase fusions for the purpose of ‘altering the enzyme’s specificity to create novel
polymerases’ (see column 23, lines 14-24).” Brief, p. 16. The appellants further argue
12
Page: Previous 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Next
Last modified: November 3, 2007