Types of Enzyme Inhibition with Examples

In this types of enzyme inhibition with examples post we have briefly explained about different types of enzyme inhibition, reversible inhibition and irreversible inhibition reactions with examples.

Different Types of Enzyme Inhibition

An inhibitor is a chemical that binds to an enzyme and reduces the enzyme’s catalytic activity. Antioxidants, for example, are added to food as inhibitors to delay deterioration when exposed to air (oxygen). 

However, numerous studies show the relevance for the pharmaceutical industry of enzyme inhibitors. In order to discover various metabolic pathways, the enzyme inhibitor research gave useful information on the mechanisms of enzyme activity. Enzyme inhibitor classes: reversible and irreversible Enzyme Inhibitors.

Reversible inhibition

The inhibitors do not bind the enzyme covalently to quick full-blown inhibition for reversible inhibition. Reversible inhibitors can therefore be readily eliminated by dilution in order to reduce the enzyme-inhibitor combination or dialysis. Three forms of inhibition of reversible enzymes exist:

Competitive Inhibition,

Non-Competitive Inhibition

Uncompetitive Inhibition

Competitive Inhibition

Enzyme Inhibition

Different Types of Enzyme Inhibition: Competitive Inhibition

In most cases, a competitive inhibition may be reversed. A competitive inhibitor is referred to as a substrate analogue if it closely mimics the substrate. The inhibitor competes with the substrate and binds to the enzyme’s active site, but it is not catalysed.

The enzyme will not be available for substrate binding as long as the competitive inhibitor is attached to the active site. The inhibition can be reversed by raising the substrate concentration.

Non-Competitive Inhibition

Enzyme Inhibition

Different Types of Enzyme Inhibition: Non-Competitive Inhibition 

Non-competitive inhibitors bind to free enzyme or ES complex at a location on the enzyme surface other than the active site. This causes the enzyme’s conformation and active site to shift, making it impossible for the substrate to attach to the enzyme efficiently.

Unlike competitive inhibitors, this kind of inhibitor has no structural similarity to the substrate. Non-competitive inhibitors have no effect on the enzyme-substrate interaction. However, catalysis is inhibited, perhaps due to a conformational change in the enzyme.

Uncompetitive Inhibition

Enzyme Inhibition

Different Types of Enzyme Inhibition: Uncompetitive Inhibition 

Inhibitors that aren’t competitive bind solely to the ES complex. The inhibitor’s binding, on the other hand, has an effect on the substrate’s binding. This sort of inhibition is unbreakable.

An allosteric effect occurs when the inhibitor binds to a different location on the enzyme than the substrate. This attachment to an allosteric site causes the enzyme’s conformation to alter, lowering the substrate’s affinity for the active site.

Irreversible inhibition

The irreversible inhibitors merge covalently with or affect a useful group on an enzyme that is essential for the enzyme’s activity or form a particularly stable non-covalent association. Irreversible inhibitors are subdivided into two groups; active site directed and suicide inhibition.

Directed Inhibition

Active site-directed irreversible inhibitors of enzymes are also known as active site-directed inactivating reagents, affinity labels, and photo affinity labels. They combine the features of a substrate, or substrate analogue, with those of a group-specific reagent, as in affinity labelling, and have been used to determine the amino acid residues that are present in the active site and involved in enzymic catalysis.

Suicide Inhibition

Non-competitive inhibition involves binding to and modification of the enzyme in such a way as to affect its catalytic activity. Suicide inhibition involves the generation of a reactive metabolite of the substrate that binds to the enzyme inhibiting its activity toward its or other substrates

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