inhibitorok

An inhibitor is a substance or process that decreases the rate or extent of a biochemical reaction or metabolic pathway. In biochemistry, inhibitors commonly target enzymes by reducing their catalytic activity. Inhibitors can be reversible, forming non-covalent complexes, or irreversible, often forming covalent bonds with the enzyme. They can also be classified by their mode of action: competitive inhibitors resemble the substrate and bind to the active site; noncompetitive inhibitors bind to an allosteric site independent of substrate binding; uncompetitive inhibitors bind only to the enzyme–substrate complex; mixed inhibitors display properties of more than one class.

Reversible inhibitors may be removed by dilution or dialysis, whereas irreversible inhibitors typically permanently inactivate the enzyme. In metabolic regulation, feedback inhibition is a natural type of regulative inhibitor example where end-products inhibit an upstream enzyme to regulate flux.

Common examples include pharmacological enzyme inhibitors: ACE inhibitors (such as captopril), statins (HMG-CoA reductase inhibitors), protease inhibitors used in antiviral therapy, and aspirin which irreversibly inhibits cyclooxygenase. Inhibitors are also used as tools in research to probe enzyme function or to modulate signaling pathways. In molecular biology, inhibitors can interfere with DNA polymerases and other enzymes, and may need to be removed or neutralized to ensure experimental success.

Quantitative properties such as IC50, Ki, and Kd describe inhibitor potency and affinity. Ki measures the affinity of the inhibitor for the enzyme, while IC50 is the inhibitor concentration needed to reduce activity by half under specific conditions. The choice of inhibitor type depends on the desired specificity and the therapeutic or experimental goals.