Enzyme Activity and RedOx Reactions Flashcards

A set of vocabulary flashcards covering the concepts of enzyme kinetics, redox reactions, and the specific laboratory procedures involving peroxidase and guaiacol.

Catalyst

A chemical agent that speeds up a reaction without being consumed by the reaction.

Enzyme

A catalytic protein that speeds up metabolic reactions by lowering energy barriers.

Sucrase

The specific enzyme that catalyzes the hydrolysis of sucrose ($C_{12}H_{22}O_{11}$) into fructose ($C_6H_{12}O_6$) and glucose ($C_6H_{12}O_6$).

Redox Reactions

Chemical reactions that transfer electrons between reactants, also known as oxidation-reduction reactions.

Oxidation

A process in a redox reaction where a substance loses electrons.

Reduction

A process in a redox reaction where a substance gains electrons, thereby reducing the amount of positive charge.

Substrate

The reactant that an enzyme acts on.

Enzyme-substrate complex

The structure formed when an enzyme binds to its specific substrate.

Active site

The specific region on the enzyme where the substrate binds, characterized by a complementary fit.

Activation energy ($E_A$)

The initial free energy of activation needed to start a chemical reaction, often supplied as thermal energy from the surroundings.

Competitive inhibition

A process where a competitive inhibitor mimics the substrate and enters the active site, blocking the substrate from binding.

Noncompetitive inhibition

A process where an inhibitor binds to a region of the enzyme other than the active site, changing the enzyme's shape and reducing its effectiveness.

Denaturation

A factor that influences enzyme activity by altering the protein's unique structure, thereby affecting its function.

Hydrogen peroxide ($H_2O_2$)

A metabolic waste product from cellular respiration and a very strong oxidizer that can damage DNA, lipids, and proteins if not neutralized.

Peroxidase

An enzyme found in cells like horseradish and turnips that uses hydrogen peroxide as a substrate.

Guaiacol

An electron donor used in lab experiments that is colorless in its reduced form but turns brown (amber) when oxidized.

Dye-coupled reaction

A reaction such as $H_2O_2 + \text{guaiacol} + \text{peroxidase} \rightarrow H_2O + \text{guaiacol (oxidized)} + \text{peroxidase}$, where color change correlates with enzymatic breakdown.

Spectrophotometer

An instrument used to measure the absorbance of a solution, which indicates the amount of oxidized guaiacol and the rate of enzyme activity.