Appeal No. 2005-1745
Application No. 09/161,680
The same is true with the “lock and key” mechanism of interaction. There the enzyme
must bind to the substrate albeit by noncovalent bonds. Thus, when the specification, as
originally filed, states that alteration of substrate specificity “means that enzymes have
been subjected to the method are able to convert substrates which they were previously
unable to convert” it could be interpreted to mean that the method the enzyme will “bind”
or interact either by “lock and key” or “induced fit” with a completely new substrate.
We recognize that the specification, as originally filed, further states that the
enzymes were unable to convert the new substrates “because the affinity of the enzyme
for the substrate was too low (= high KM) and/or the catalytic activity (= kcat) of the
enzyme is too low.” Specification, p. 3, lines 45-47. These properties of affinity and/or
activity differ from the enzyme’s structural interactions and thus are the source of the
examiner’s concerns. As set forth in the specification, KM measures the affinity of the
enzyme for the substrate. The KM (the Michaelis-Menten constant) expresses “the
mathematical relationship between the initial rate of an enzyme catalyzed reaction, the
concentration of the substrate and certain characteristics of the enzyme.” Lehninger, p.
192.8 That is,
Because of the way that enzymes work, there is a limit to the amount of a
substrate that a single enzyme can process at a given time. If the concentration
8 Lehninger, in Biochemistry, 2nd Edition, Worth Publishers, Inc., New York
(1975). Relevant pages attached.
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