Appeal No. 2004-1935 Page 7
Application No. 09/308,403
peroxidase-catalyzed polymerization using exogenous hydrogen peroxide, while
Crawford teaches peroxidase-catalyzed depolymerization using hydrogen peroxide
generated in situ. Therefore, Appellant and Dr. Greenshields argue, those skilled in the
art would have expected that any peroxidase-catalyzed reaction that relied on in situ-
generated hydrogen peroxide would be expected to result in depolymerization, not
polymerization.
This position is scientifically untenable. It ignores the obviously crucial difference
between Greenshields’ reaction and Crawford’s: they are catalyzed by different
peroxidase enzymes. Greenshields uses horseradish peroxidase to catalyze the
polymerization of a hemicellulose-containing mixture (see column 6, lines 34-40), while
Crawford uses a lignin peroxidase to catalyze depolymerization of lignin (see the
abstract). Even the instant specification recognizes that, while hydrogen peroxide is a
necessary component of the peroxidase-catalyzed reaction, it is only a substrate – the
reaction is catalyzed by the peroxidase enzyme. See the paragraph bridging pages 7
and 8, which shows that peroxidases catalyze reactions of the general formula:
H2O2 + H2A → 2H2O + A
where H2O2 is the chemical formula of hydrogen peroxide and H2A is an oxidizable
substrate.
Thus, those skilled in the art would have expected that horseradish peroxidase,
in the presence of hydrogen peroxide, would catalyze the polymerization of
Greenshields’ hemicellulose-containing composition, regardless of whether the
hydrogen peroxide was exogenously added or generated in situ. In other words, while
Crawford might teach away from substituting a lignin peroxidase for the horseradish
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