Question

Cyanide kills animals by inhibiting cytochrome oxidase (an enzyme of respiration) by binding irreversibly with copper. It does not bind with active sites. This is an example of

• A. feedbackinhibition
• B. all of the above
• C. non competitive inhibition
• D. competitive inhibition

Answer 1

The correct option is C non competitive inhibition

$\text{Factors affecting enzyme activity}$

The efficiency with which an enzyme can function depends on many factors, like- temperature, pH, substrate concentration, presence of inhibitors.

$\text{Inhibitors}$

Inhibitors are chemicals that stop enzyme activity. Based on their mode of action, there are the following types of inhibitors:-

• Competitive inhibitors
• Non-competitive inhibitors
• Allosteric inhibitors
• Irreversible inhibitors

$\text{Non-Competitive inhibition}$

• Non-competitive inhibition is when the structure of the inhibitor and the substrate is different.
• It binds to a site other than the active site either irreversibly or reversibly, changing the shape of the active site and thus rendering the enzyme inactive.
• For example, cyanide inhibits cytochrome oxidase activity by combining irreversibly with copper.

$\text{Final answer : non competitive inhibition}$