INHIBITORS: COMPETITVE
Definition of Competitive Inhibitors
Competitive inhibitors are inhibitors that compete with substrates for the active site. They resemble the
substrate in that they can fit into the active site, fooling the enzyme into thinking that they are
substrates. The active site is a region on an enzyme to which a particular protein or substrate can bind.
The active site will thus only allow one of the two complexes to bind to the site, either allowing a
reaction to occur or yielding it. If the inhibitor successfully binds, it forms an enzyme-inhibitor complex,
preventing the substrate from binding and reacting.
Reversible Inhibition
Competitive inhibition is usually reversible. This is because the binding of the competitive inhibitor to
the enzyme is non-covalent and does not involve the formation of strong chemical bonds.
The inhibitor can dissociate from the enzyme, freeing up the active site for substrate binding.
Characteristics of competitive inhibitors
1. Structural Similarity:
Competitive inhibitors closely resemble the structure of the substrate for the enzyme.
They often share similarities in shape and chemical structure, allowing them to compete for the active
site.
2. Regulation of Enzyme Activity:
Competitive inhibition is a natural regulatory mechanism in cells, controlling the activity of enzymes
involved in various metabolic pathways.
3. Drug Development Significance:
Understanding competitive inhibition is crucial in drug design, where drugs can be developed to
competitively inhibit specific enzymes for therapeutic purposes.
Such as erectile dysfunction medication and gout medication
Examples of Competitive Inhibitors
1) Antimetabolite Methotrexate
Target Enzyme: Dihydrofolate reductase (DHFR)
which is used to slow cancer growth
2) Ibuprofen
target enzyme: Cyclooxygenase (COX)
Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain and inflammation.
3) Statins
Target Enzyme: HMG-CoA reductase
Statins are commonly prescribed for reducing cholesterol levels in the treatment of cardiovascular
diseases.
Closing
competitive inhibitors are essential components in the intricate regulation of enzymatic activity. Their
study not only enhances our understanding of fundamental cellular processes but also contributes to
the development of therapeutic interventions in medicine and biotechnology.