Rapid Equilibrium bisubstrate systems substrate inhibition

However, the primary double reciprocal plots of some rapid equilibrium systems are identical. In rapid equilibrium systems, in the presence of the products of reaction, the primary reciprocal plots are very characteristic and depend on the number and type of enzyme-substrate and enzyme-product complexes that can form. Therefore, in order to distinguish between different t5q>es, one must revert to product inhibition patterns that can easily distinguish between aU types of rapid equilibrium bisubstrate systems (Plowman, 1972 Segel, 1975) (Table 2). 

As a mle, a noncompetitive inhibition occurs only if there are more than one substrate or product (Todhunter, 1979 Fromm, 1995). For example, a noncompetitive inhibition will take place in a random bisubstrate reaction, when an inhibitor competes with one substrate while the other substrate is varied. Thus, the equilibria shown below describe a Rapid Equilibrium Random bisubstrate system in which an inhibitor competes with A but allows B to bind. 

Figure 2. Noncompetitive inhibition. Rapid Equilibrium Random bisubstrate system with an inhibitor noncompetitive with B. Graphical presentation of Eq. (S-io), with A as a constant and B as a variable substrate.

Substrate Inhibition in a Rapid Equilibrium Random Bisubstrate System... 

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