Enzymhemmern

Enzymhemmern, or enzyme inhibitors, are substances that decrease or block the activity of enzymes. They can act through various mechanisms and are central to biochemistry, pharmacology, and medicine. By binding to an enzyme's active site or to other parts of the molecule, inhibitors can reduce the rate of the catalyzed reaction or prevent substrate conversion altogether.

In reversible inhibition, the inhibitor can dissociate from the enzyme, allowing activity to resume. Reversible inhibitors include competitive inhibitors that resemble the substrate and compete for the active site, noncompetitive inhibitors that bind to a different site, and uncompetitive inhibitors that bind only to the enzyme-substrate complex. Irreversible inhibitors form covalent bonds or long-lasting associations, permanently inactivating the enzyme or requiring new synthesis of enzyme molecules to restore activity. Some inhibitors are mechanism-based or suicide inhibitors, becoming reactive only after attempted catalysis.

Enzyme inhibitors have wide applications in research and medicine. They are used as tools to dissect enzymatic pathways and to probe enzyme function. In medicine, many drugs act as enzyme inhibitors, for example inhibitors of cyclooxygenase to reduce inflammation and pain, inhibitors of HMG-CoA reductase to lower cholesterol, or protease inhibitors used in antiviral therapy. Other inhibitors target enzymes in neurotransmitter metabolism or signal transduction, with implications for treating neurological and endocrine disorders.

Potential drawbacks include off-target effects, toxicity, and drug interactions, since many enzymes are present in multiple tissues. Drug design and safety assessment aim to balance efficacy against adverse effects.