Chemistry Reference
In-Depth Information
3
Evolution of Synthetic Polymers with Enzyme-like Catalytic
Activities
Irving M. Klotz and Junghun Suh
3.1
Introduction: Conceptual Background
One of the most remarkable types of homogeneous catalyst is the class of naturally-
occurring substances called enzymes. In the course of a billion years, nature has devel-
oped a range of macromolecules with high catalytic efficiency and extraordinary ver-
satility in reactions whose rates can be accelerated. It has been a challenge for decades,
therefore, to try to emulate the catalytic properties of enzymes with synthetic macro-
molecules of nonbiological origin (synzymes).
An enzyme is a macromolecule. It has long been recognized [1-3] that this macro-
molecule, M, operates through two sequential processes (Eq. 1): (1) binding of the
substrate S and (2) provision of a molecular environment conducive to the chemical
transformation:
ð
1
Þ
Particular enzymes show molecular selectivity in the binding step and provide specific
functional groups and environments to facilitate the catalytic step.
In a rational approach to the reproduction of enzyme-like catalytic behavior with a
synthetic polymer one should use, therefore, a two-step plan: (1) fabrication of binding
sites on a suitable macromolecular framework; (2) introduction of groups to provide an
environment of specific functional side chains that facilitate formation of the transi-
tion state in the catalytic step.
