Introduction to Enzyme Inhibition

These flashcards cover key terms and concepts related to enzyme inhibition discussed in the lecture, including types of inhibitors and their effects on enzyme kinetics.

Irreversible Inhibitors

Agents that covalently modify a critical residue in the catalytic site of an enzyme, permanently inactivating it.

Reversible Inhibitors

Inhibitors that do not permanently alter the enzyme and can be removed, allowing normal activity to resume.

Competitive Inhibitor

An inhibitor that binds to the catalytic site of the enzyme and competes with the natural substrate, increasing the Km but not affecting Vmax.

Noncompetitive Inhibitor

An inhibitor that binds to a regulatory site of the enzyme, lowering Vmax without affecting Km.

Km (Michaelis constant)

The substrate concentration at which the reaction rate is half of Vmax; indicative of the affinity of the enzyme for its substrate.

Vmax

The maximum rate of reaction achievable by an enzyme when it is saturated with substrate.

Aspirin

An irreversible inhibitor that acetylates a serine residue in cyclooxygenase enzymes, preventing inflammation and pain.

Sarin Gas

An irreversible inhibitor that phosphorylates serine in acetylcholinesterase, causing paralysis and increased acetylcholine concentration.

Methotrexate

A competitive inhibitor that binds to the active site of enzymes and can be overcome by increasing substrate concentration.

Uncompetitive Inhibitor

An unusual inhibitor that binds only to the enzyme-substrate complex and decreases both Km and Vmax, but is rarely encountered.