Enzyme Inhibition and Regulation

These flashcards cover key terms related to enzyme inhibition, including both irreversible and reversible inhibitors, their mechanisms, and their effects on enzyme kinetics.

Irreversible Inhibitors

Agents that covalently modify a critical residue in the catalytic site of the enzyme, resulting in permanent inactivation.

Covalent Bond

A strong chemical bond formed when two atoms share electrons, often involved in irreversible inhibition of enzymes.

Cyclooxygenase (COX)

An enzyme involved in converting lipid precursors into prostaglandins, which transmit pain and inflammation signals.

Prostaglandins

Chemical mediators that transmit pain sensation and are involved in the inflammatory response.

Aspirin

A medication that functions as an irreversible inhibitor of cyclooxygenase, blocking pain and inflammation by permanently inhibiting the enzyme.

Competitive Inhibitors

Inhibitors that bind to the active site of the enzyme, preventing substrate binding and increasing the Km without affecting Vmax.

Km (Michaelis constant)

A measure of the substrate concentration required to reach half the maximum reaction velocity (Vmax); it increases with competitive inhibition.

Noncompetitive Inhibitors

Inhibitors that bind away from the active site, lowering Vmax but not affecting Km, as they do not prevent substrate binding.

Vmax

The maximum rate of reaction achievable by an enzyme; unaffected by competitive inhibitors but decreased by noncompetitive inhibitors.

Regulatory Site

A site on an enzyme where noncompetitive inhibitors bind, which alters the enzyme's configuration but does not affect substrate binding.