Appeal No. 2005-1745
Application No. 09/161,680
change in a reaction catalyzed by an enzyme are the substrates of that enzyme.”
Darnell, p. 55, col. 2, para. 3.7 “Enzyme molecules have two important regions, or sites:
one that recognizes and binds the substrate(s), and one that catalyzes the reaction once
the substrate(s) have been bound. . . . In some enzymes the catalytic site is part of the
substrate-binding site. These two regions are called, collectively, the active site.” Id., p.
56, col. 1, para. 2. “The specificity of an enzyme is determined by the different rates at
which it catalyzes closely similar chemical reactions or by its ability to distinguish
between closely similar substrates.” Id., para. 1. With either event, the first step in
enzyme catalysis requires the binding of the enzyme to the substrate. In this regard,
there are two mechanisms of interaction. One is known as the “lock and key”
mechanism whereby the enzyme and substrate simply fit together forming “a complex
stabilized by a variety of noncovalent bonds.” Darnell, p. 60, para. 1. The other
mechanism, known as “induced fit” occurs when
the substrate induces a conformational change in the enzyme that causes the
catalytic residues to become positioned correctly. Molecules that attach to the
substrate-binding site, or recognition site, of the enzyme but that do not induce a
conformational change are not substrates of that enzyme. Thus an enzyme
differentiates between a substrate and a nonsubstrate in two ways: Does the
potential substrate bind to the enzyme? If so, does it produce a conformational
change? When both criteria are met, the enzyme-substrate complex is said to
demonstrate an induced fit [second emphasis added] Darnell, p. 60, para. 2.
7 Darnell et al. (Darnell), Molecular Cell Biology, 2nd Edition, Scientific American
Books, distributed by W.H. Freeman and Company, NY, 1990. Relevant pages
attached.
19
Page: Previous 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next
Last modified: November 3, 2007