Biology Reference
In-Depth Information
There are 18 kinetic constants (represented by the 18 arrows in Fig. 4-2) to
be measured. Since this is obviously not possible for most enzymes, drastic
simplification is necessary. For most enzymatic reactions, the co-enzyme
NAD is omitted even though the concentration of reduced NAD is actually
measured. Thus, sufficient amount of NAD must be added to saturate the
enzyme with the co-enzyme. Then the production of the product is
considered to be irreversible (Fig. 4-3).
Figure 4-3.
Simplified enzymatic reaction.
As a result, 18 kinetic constants are reduced to three. This simplified
reaction is usually referred to as the Michaelis-Menten kinetics (Michaelis
and Menten, 1913). Rate equations are needed to determine them.
RATE EQUATIONS
From Fig. 4-2, the rate equations can be written down using the directions of
the arrow:
and
