Inhibitors and its types
Agents which inactivates the enzyme activities is known as inhibitors.In other word the chemical substances which reduced the velocity of particular enzyme is called inhibitors.Basically they are of two type reversible and irreversible.
reversible are of 3 types ie
1.Competitive inhibitors:
The activity of enzyme is inhibit by blocking to active site by an inhibitors substances .The inhibitors resemble the substrate molecule in its molecular organization instead of enzyme substrate.It depend upon the concentration of substrate and inhibitors.For example Malonic acid(an inhibitors) competes with Succinic acid for the enzyme succinic acid dehydrogenase .This enzyme catalysed the oxidation of succinic acid in the process of cellular respiration.Both succinic acid and malonic acid resemble a lot in their structure.
2Non competitive inhibitors:
In non competitive inhibitors the inhibitors doesn't compete for the active site of the enzyme but it attached itself on the some others site of the enzyme .The attachment change the physical dimension of the active sites of the enzyme as a result the substrate is not able to form the complex with their enzyme and the reaction inhibits.For example ,Cyanide inhibit the activity of the enzyme Cytochrome oxidase as a result it cannot act on the substrate cytochrome-c ,Cytochrome oxidase is an important mitochondrial enzyme ,thus Cyanide kill the animals as it can immediately block the process of cellular respiration.In this case the Cyanide has no structural similarity with the substrate.
3.Allosteric inhibitors:
It has been noted that when metabolites or end products accumulate in the cell after the enzymatic activity ,they inhibits their own production .These metabolites are some specific low molecular substances bind with the specific site of enzyme other than its active site.Such binding increase or decrease the rate of reaction .It is the mechanism by which the the activity of enzyme is inhibits.For instance accumulation of Glucose 6 phosphate inhibits the activity of hexokinase in glycolysis pathway.
reversible are of 3 types ie
1.Competitive inhibitors:
The activity of enzyme is inhibit by blocking to active site by an inhibitors substances .The inhibitors resemble the substrate molecule in its molecular organization instead of enzyme substrate.It depend upon the concentration of substrate and inhibitors.For example Malonic acid(an inhibitors) competes with Succinic acid for the enzyme succinic acid dehydrogenase .This enzyme catalysed the oxidation of succinic acid in the process of cellular respiration.Both succinic acid and malonic acid resemble a lot in their structure.
2Non competitive inhibitors:
In non competitive inhibitors the inhibitors doesn't compete for the active site of the enzyme but it attached itself on the some others site of the enzyme .The attachment change the physical dimension of the active sites of the enzyme as a result the substrate is not able to form the complex with their enzyme and the reaction inhibits.For example ,Cyanide inhibit the activity of the enzyme Cytochrome oxidase as a result it cannot act on the substrate cytochrome-c ,Cytochrome oxidase is an important mitochondrial enzyme ,thus Cyanide kill the animals as it can immediately block the process of cellular respiration.In this case the Cyanide has no structural similarity with the substrate.
3.Allosteric inhibitors:
It has been noted that when metabolites or end products accumulate in the cell after the enzymatic activity ,they inhibits their own production .These metabolites are some specific low molecular substances bind with the specific site of enzyme other than its active site.Such binding increase or decrease the rate of reaction .It is the mechanism by which the the activity of enzyme is inhibits.For instance accumulation of Glucose 6 phosphate inhibits the activity of hexokinase in glycolysis pathway.
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