Introduction to Enzymes The following has been excerpted from a
very popular Worthington publication which was originally
published in 1972 as the Manual of Clinical Enzyme Measurements.
While some of the presentation may seem somewhat dated, the
basic concepts are still helpful for researchers who must use
enzymes but who have little background in enzymology. Enzyme
Kinetics: Energy Levels Chemists have known for almost a century
that for most chemical reactions to proceed, some form of energy
is needed. They have termed this quantity of energy, "the energy
of activation." It is the magnitude of the activation energy
which determines just how fast the reaction will proceed. It is
believed that enzymes lower the activation energy for the
reaction they are catalyzing. Figure 3 illustrates this concept.
The enzyme is thought to reduce the "path" of the reaction. This
shortened path would require less energy for each molecule of
substrate converted to product. Given a total amount of
available energy, more molec