Indicate whether the following circumstances would tend to increase, decrease or have no effect on the rate of enzyme activity.
1.adding more substrate but keeping the amount of enzyme of the same
2.adding more enzyme but keeping the amount of substrate the same
3. adding a competitive inhibitor
4.adding more substrate when the rate is at saturation
5.transferring salivary amylase from an environment of pH7 to pH3
6.a genetic mutation causes a change in the active site.
To indicate whether the given circumstances would increase, decrease, or have no effect on the rate of enzyme activity, let's analyze each situation separately:
1. Adding more substrate but keeping the amount of enzyme the same: Increasing the substrate concentration generally leads to an increase in enzyme activity up to a certain point. This is because a higher substrate concentration provides more opportunities for the enzyme to bind and catalyze the reaction. However, once the enzyme becomes saturated, adding more substrate will not further increase the reaction rate since all available enzyme-active sites are already occupied. Therefore, initially, adding more substrate would increase the rate of enzyme activity, but it would eventually plateau.
2. Adding more enzyme but keeping the amount of substrate the same: Increasing the enzyme concentration will generally increase the rate of enzyme activity. This is because more enzyme molecules are available to interact with the substrate, thereby increasing the chances of successful collisions and catalysis. As long as the substrate concentration is not limiting, adding more enzyme will directly increase the rate of the reaction.
3. Adding a competitive inhibitor: Competitive inhibitors are molecules that can bind to the active site of an enzyme, competing with the substrate for binding. The presence of a competitive inhibitor reduces the rate of enzyme activity. This is because when the inhibitor occupies the active site, it prevents the substrate from binding and hinders catalysis. As a result, adding a competitive inhibitor decreases the rate of enzyme activity.
4. Adding more substrate when the rate is at saturation: When the enzyme is already saturated with substrate (i.e., all active sites are occupied), adding more substrate has no effect on the rate of enzyme activity. The reaction rate will remain constant since all available enzyme molecules are already engaged in catalysis. In this case, adding more substrate does not increase the rate of enzyme activity.
5. Transferring salivary amylase from an environment of pH 7 to pH 3: Enzymes have optimal pH conditions at which they exhibit maximum activity. Altering the pH outside the optimal range can significantly affect enzyme activity. For example, transferring salivary amylase from pH 7 to pH 3, which is highly acidic, would likely decrease the rate of enzyme activity. The change in pH can disrupt the enzyme's tertiary structure, leading to partial or complete denaturation, thus reducing its catalytic efficiency.
6. A genetic mutation causes a change in the active site: The active site is a region on the enzyme where the substrate binds and catalysis occurs. If a genetic mutation alters the active site's structure or composition, it can disrupt the binding affinity between the enzyme and the substrate. Consequently, the rate of enzyme activity may be increased, decreased, or completely abolished, depending on the specific changes in the active site caused by the mutation. However, the precise effect on the rate of enzyme activity would depend on the nature and extent of the mutation.