Optometry Admission Test (OAT) Practice

What does the term allosteric regulation refer to?

1. The inhibition of enzymes by substrate competition

2. The binding of an effector molecule at an allosteric site

3. The irreversible modification of active sites

4. The synthesis of proteins in response to hormones

The correct answer is: The binding of an effector molecule at an allosteric site

Allosteric regulation refers to the process wherein the regulation of an enzyme occurs through the binding of an effector molecule at a site other than the enzyme's active site, known as the allosteric site. When an effector molecule binds to this site, it induces a conformational change in the enzyme, ultimately affecting the enzyme's activity. This can lead to either an increase (positive allosteric regulation) or a decrease (negative allosteric regulation) in the enzyme's catalytic activity. The importance of this mechanism lies in its ability to finely tune enzyme activity in response to the needs of the cell, allowing a more sophisticated level of regulation compared to simple competitive inhibition, where the substrate directly competes with the enzyme for the active site. Allosteric regulation can integrate multiple signals and provide a means for metabolic pathways to adapt dynamically to changing conditions.