Enzymes Flashcards

Flashcards to review key concepts about enzymes from Biology 1 lecture.

Enzyme

Biological catalyst that speeds up chemical reactions without being used up.

Active Site

The region on an enzyme where the substrate binds and the reaction occurs.

Lock-and-Key Model

An older model proposing that the active site and substrate fit perfectly together like a lock and key.

Induced-Fit Model

A model where the active site of an enzyme changes shape slightly to better fit the substrate.

Activation Energy

The energy 'barrier' that must be crossed to facilitate a chemical reaction; enzymes lower this energy.

Optimum Temperature

The temperature at which an enzyme functions most effectively (usually 37°C in humans).

Optimum pH

The pH at which an enzyme is most active; each enzyme has its own optimum pH.

Enzyme Cofactor

Non-protein component required for the proper functioning of an enzyme.

Apoenzyme

The protein portion of an enzyme and it is inactive without a cofactor.

Holoenzyme

The whole enzyme and it is active when an apoenzyme binds with a cofactor.

Enzyme Activators (Metal Ions)

Inorganic metal ions that attach loosely to the enzyme, changing the active site to make it suitable for substrate binding.

Coenzymes

Non-protein organic molecules that attach loosely to the active site of an enzyme and transfer chemical groups, atoms, or electrons.

Prosthetic Group

Non-protein molecule that attaches permanently or tightly to an enzyme and involves in the catalytic function of the enzyme.

Competitive Inhibitor

A substance that competes with the normal substrate for binding to the active site of an enzyme.

Non-Competitive Inhibitor

A substance that binds to an enzyme at a site other than the active site (allosteric site), altering the shape of the enzyme and preventing substrate binding.

Allosteric Site

Site on the enzyme where a non-competitive inhibitor can bind.

Reversible Inhibition

Inhibition where the inhibitor binds temporarily to the enzyme and can be overcome by increasing substrate concentration.

Irreversible Inhibition

Inhibition where the inhibitor binds permanently to the enzyme, destroying its activity.

Feedback Inhibition

A process where the end product of a metabolic pathway inhibits an earlier enzyme in the pathway, regulating its own production.

Isoenzymes

Different forms of an enzyme that catalyze the same reaction but vary in their physical and kinetic properties.

Enzyme Specificity

The ability of an enzyme to bind and react with only one or a small number of substrates.

Enzyme Turnover Number

The maximum number of substrate molecules one enzyme molecule can convert per unit time.

Michaelis-Menten Kinetics

A model describing the rate of enzymatic reactions, relating reaction rate to substrate concentration.

Lineweaver-Burk Plot

A graphical representation of the Michaelis-Menten equation, used to determine enzyme kinetic parameters.

Enzyme Denaturation

The effect where an enzyme loses its activity due to changes in its native conformation caused by non-optimal conditions (e.g., high temperature or extreme pH).

Unimolecular Reactions

A type of enzymatic reaction where a single substrate is converted into multiple products.

Bimolecular Reactions

A type of enzymatic reaction that involves two substrates and one product.

Enzyme Assay

A method used to determine the concentrations of enzymes and substrates in a sample by measuring the rate of a reaction.

Enzyme Saturation

A condition where the rate of an enzyme-catalyzed reaction reaches its maximum, and adding more substrate will not increase the rate.

Vitamin-Derived Coenzymes

Organic molecules that contain a reactive group, which allows them to participate in a variety of catalytic reactions (e.g., NAD+, FAD, and coenzyme A).

Enzyme

Biological catalyst that speeds up chemical reactions without being used up.

Active Site

The region on an enzyme where the substrate binds and the reaction occurs.

Lock-and-Key Model

An older model proposing that the active site and substrate fit perfectly together like a lock and key.

Induced-Fit Model

A model where the active site of an enzyme changes shape slightly to better fit the substrate.

Activation Energy

The energy 'barrier' that must be crossed to facilitate a chemical reaction; enzymes lower this energy.

Optimum Temperature

The temperature at which an enzyme functions most effectively (usually 37°C in humans).

Optimum pH

The pH at which an enzyme is most active; each enzyme has its own optimum pH.

Enzyme Cofactor

Non-protein component required for the proper functioning of an enzyme.

Apoenzyme

The protein portion of an enzyme and it is inactive without a cofactor.

Holoenzyme

The whole enzyme and it is active when an apoenzyme binds with a cofactor.

Enzyme Activators (Metal Ions)

Inorganic metal ions that attach loosely to the enzyme, changing the active site to make it suitable for substrate binding.

Coenzymes

Non-protein organic molecules that attach loosely to the active site of an enzyme and transfer chemical groups, atoms, or electrons.

Prosthetic Group

Non-protein molecule that attaches permanently or tightly to an enzyme and involves in the catalytic function of the enzyme.

Competitive Inhibitor

A substance that competes with the normal substrate for binding to the active site of an enzyme.

Non-Competitive Inhibitor

A substance that binds to an enzyme at a site other than the active site (allosteric site), altering the shape of the enzyme and preventing substrate binding.

Allosteric Site

Site on the enzyme where a non-competitive inhibitor can bind.

Reversible Inhibition

Inhibition where the inhibitor binds temporarily to the enzyme and can be overcome by increasing substrate concentration.

Irreversible Inhibition

Inhibition where the inhibitor binds permanently to the enzyme, destroying its activity.

Feedback Inhibition

A process where the end product of a metabolic pathway inhibits an earlier enzyme in the pathway, regulating its own production.

Isoenzymes

Different forms of an enzyme that catalyze the same reaction but vary in their physical and kinetic properties.

Enzyme Specificity

The ability of an enzyme to bind and react with only one or a small number of substrates.

Enzyme Turnover Number

The maximum number of substrate molecules one enzyme molecule can convert per unit time.

Michaelis-Menten Kinetics

A model describing the rate of enzymatic reactions, relating reaction rate to substrate concentration.

Lineweaver-Burk Plot

A graphical representation of the Michaelis-Menten equation, used to determine enzyme kinetic parameters.

Enzyme Denaturation

The effect where an enzyme loses its activity due to changes in its native conformation caused by non-optimal conditions (e.g., high temperature or extreme pH).

Unimolecular Reactions

A type of enzymatic reaction where a single substrate is converted into multiple products.

Bimolecular Reactions

A type of enzymatic reaction that involves two substrates and one product.

Enzyme Assay

A method used to determine the concentrations of enzymes and substrates in a sample by measuring the rate of a reaction.

Enzyme Saturation

A condition where the rate of an enzyme-catalyzed reaction reaches its maximum, and adding more substrate will not increase the rate.

Vitamin-Derived Coenzymes

Organic molecules that contain a reactive group, which allows them to participate in a variety of catalytic reactions (e.g., NAD+, FAD, and coenzyme A).

Allosteric Site

The location on an enzyme where molecules bind other than the active site.

Industrial Enzymology

The use of enzymes in industrial processes for various applications.

Extracellular Enzymes

Enzymes that are produced within a cell but function outside of it.