Enzymes Flashcards

Flashcards covering key vocabulary terms related to enzymes, their function, and factors affecting enzymatic reactions.

Enzymes

Proteins that act as biological catalysts, speeding up biochemical reactions by lowering the activation energy.

Active Site

Specific region on an enzyme where the substrate binds and catalysis occurs.

Enzyme-Substrate Complex

The intermediate structure formed when a substrate molecule binds to the active site of an enzyme.

Activation Energy

The minimum amount of energy required to start a chemical reaction.

Enzyme Specificity

The characteristic of enzymes that allows them to bind to only one or a small number of structurally similar substrates.

Lock and Key Hypothesis

A model of enzyme action that suggests the enzyme and substrate possess complementary shapes that fit exactly into one another.

Induced Fit Hypothesis

A model of enzyme action describing flexible active site conformation that change shape slightly to bind the substrate more firmly.

Competitive Inhibitor

A substance that reduces enzyme activity by binding to the active site, thus preventing substrate binding.

Non-Competitive Inhibitor

A substance that reduces enzyme activity by binding to a site other than the active site, altering the enzyme's conformation.

Allosteric Inhibitor

A type of non-competitive inhibitor that binds to an allosteric site on the enzyme, stabilizing the inactive form and decreasing substrate affinity.

Vmax

The maximum rate at which an enzyme can catalyze a reaction when saturated with substrate.

Km (Michaelis Constant)

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

Cofactor

Non-protein chemical compound that is bound to a protein and is required for the protein's biological activity

Coenzyme

A type of cofactor; loosely associates with enzyme during reaction, often derived from vitamins.

Prosthetic Group

A type of cofactor; tightly bound to enzyme on a permanent basis.

Holoenzyme

A complete, catalytically active enzyme together with its bound coenzyme and/or metal ions.

Apoenzyme

The protein part of an enzyme.

Optimum Temperature

The temperature at which an enzyme exhibits maximum activity.

Optimum pH

The pH at which an enzyme exhibits maximum activity.

End-product Inhibition

The process where the end product of a metabolic pathway inhibits an enzyme earlier in the pathway.