Hi,
I was wondering for competitive vs. noncompetitive inhibition, does anything ever happen at the active site, or does the inhibitor only act on the allosteric?
Thanks,
Ahsan
Hi Ahsan,
In competitive inhibition, the inhibitor competes with the substrate for binding to the active site of the enzyme. This means that the inhibitor and the substrate cannot bind to the active site at the same time. The inhibitor typically resembles the substrate in structure and binds reversibly to the active site, forming an enzyme-inhibitor complex. This prevents the substrate from binding to the active site and slows down the catalytic reaction.
On the other hand, in noncompetitive inhibition, the inhibitor binds to a site other than the active site, known as an allosteric site. This allosteric binding induces a conformational change in the enzyme's structure, which affects the active site's shape and reduces the enzyme's activity. Noncompetitive inhibitors can bind to the enzyme regardless of whether the substrate is present or not because they do not compete with the substrate for binding.
To determine which type of inhibition is occurring, experimentation can be done. A common method is to vary the concentration of the substrate and measure the enzyme's activity in the presence and absence of the inhibitor. If the inhibitor only affects the enzyme's activity in the presence of the substrate, it is likely competitive inhibition. If the inhibitor reduces the enzyme's activity irrespective of the substrate concentration, it is likely noncompetitive inhibition.
I hope this explanation helps! Let me know if you have any further questions.