Question

A variety of factors influence enzyme activity. Substances that bind to the enzyme and interfere with substrate binding or catalysis are inhibitors. Identify the type of inhibition associated with each of the descriptions and examples by classifying each statement as irreversible, competitive, or mixed inhibition.

Answer 1

Irreversible inhibition:

• DIPF permanently modifies the hydroxyl group of a Ser residue at the active site

Competitive inhibition:

• Binding by the inhibitor increases Km but not Vmax
• Malonate, which resembles succinate, binds to the succinate dehydrogenase active site

Mixed inhibition:

• Binding by the inhibitor increases Km but decreases Vmax
• The Al₃⁺ ion binds to acetylcholinesterase or to the acetylcholinesterase-substrate complex

What are the classifications?

Irreversible inhibition occurs when an inhibitor permanently modifies an enzyme, as seen with DIPF modifying the hydroxyl group of a Ser residue. Competitive inhibition involves an inhibitor binding to the active site, increasing Km but not affecting Vmax. Malonate, resembling succinate, competitively binds to succinate dehydrogenase.

Mixed inhibition exhibits characteristics of both competitive and non-competitive inhibition, altering both Km and Vmax. In the case of the Al₃⁺ ion, it binds to acetylcholinesterase or the acetylcholinesterase-substrate complex, influencing both substrate binding and catalysis. Each form of inhibition provides insights into enzyme regulation and function.

Complete question:

A variety of factors influence enzyme activity. Substances that bind to the enzyme and interfere with substrate binding or catalysis are inhibitors. Identify the type of inhibition associated with each of the descriptions and examples by classifying each statement as irreversible, competitive, or mixed inhibition.

Irreversible inhibition

Competitive inhibition

Mixed inhibition

Answer Bank

binding by the inhibitor increases K_{m} but decreases Vmax

binding by the inhibitor increases K m. but not V max

malonate, which resembles succinate, binds to the succinate dehydrogenase active site

inhibitor may permanently modify an enzyme

DIPF permanently modifies the hydroxyl group of a Ser residue at the active site

the Al₃⁺ ion binds to acetylcholinesterase or to the acetylcholinesterase-substrate complex

Answer 2

Step-by-step explanation:

Irreversible inhibitors are inhibitors whose action are not reversible. They function by modifying enzyme in a covalent way leading to the formation of new functional group.

Irreversible inhibitors are specific to certain enzymes. Examples is inhibitor that are suicidal they makes inhibitor reactive.

Competitive inhibition are Inhibitor that are competitive in nature they resemble one of the substrate of the enzyme and are been bind to by mistake. Example is an inhibitor that resemble folate an enzyme substrate. Enzyme therefore binds to the inhibitor assuming its folate because they are identical.