Warm Up 10/10

1. What is denaturation?
Denaturation is changing the structure of an enzyme (or other protein) so that it can no longer carry out its function.  Enzymes are denatured at very high temperatures and extreme pHs.

2.What does a graph for increasing substrate concentration of an enzyme look like? Describe it...
At low substrate concentrations, enzyme activity increases steeply as substrate concentration increases.  Random collisions between substrate and active site happen more frequently with higher substrate concentrations.  At high substrate concentrations, most of the active sites are occupied, so raising the substrate concentration has little effect on enzyme activity and the graph begins to plateau.

3. Compare competitive/non-competitive inhibition.
Competitive inhibition is when an inhibitor similar to the substrate binds to the active site, blocking the active site and preventing substrate binding.  The presence of a competitive inhibitor reduces the rate of reaction, but increasing the concentration of substrate can reduce the effect of the inhibitor.
Non-competitive inhibition is when an inhibitor not similar to the substrate binds to a site other than the active site (allosteric site) and changes the active site, preventing the substrate from binding to the active site.

4. Discuss lock-and-key vs. induced-fit.
The lock-and-key hypothesis states that enzymes are substrate-specific and the substrate fitting in the enzyme is like a key fitting in a lock.  This does not explain the broad specificity of some enzymes.  The induced-fit model helps explain how substrates change to fit an enzyme.  The induced-fit model says the active site may undergo conformational change to better fit the substrate.  The active site may change shape or configuration.  This change is induced by the substrate.