Enzymes and Protein Denaturation

Flashcards covering key concepts related to protein denaturation, enzyme function, and regulation.

Denaturation

A process in which proteins lose their native shape and function due to disruption of weak chemical bonds and interactions, potentially caused by heat, pH changes, or other factors.

Protein Destruction

Occurs when a denaturing agent breaks the peptide bonds holding amino acids together in a protein's primary structure.

Prolonged Fever

Can denature critical enzymes in the brain, leading to seizures and possibly death if body temperature exceeds 39°C.

Food Preservation

Curing meats or pickling vegetables can extend shelf life by denaturing the enzymes in bacteria that would otherwise spoil the food.

Blanching

Quickly dipping fruits and vegetables in boiling water to denature enzymes that cause browning when exposed to air.

Hair Straightening/Curling

Heat can denature the proteins (keratin) in hair, allowing temporary reshaping. New disulfide bridges form to hold the new shape.

Chaperone Proteins

Special proteins that aid the growing polypeptide to fold into its correct tertiary structure.

Cofactors (Enzymes)

Nonprotein substances (inorganic ions or organic coenzymes) required by some enzymes to function properly.

Competitive Inhibitor

A substance that inhibits enzyme activity by binding to the active site, blocking the substrate from binding; can be overcome by increasing substrate concentration.

Noncompetitive Inhibitor

A substance that binds to a site other than the active site on an enzyme, causing a conformational change that reduces the enzyme's affinity for its substrate.

Allosteric Regulation

The control of enzyme activity by substances binding to allosteric sites, which may inhibit or stimulate the enzyme's activity.

Allosteric Site

Receptor sites on enzymes where substances bind to regulate enzyme activity.

Activator (Allosteric)

A substance that binds to an allosteric site, stabilizing the active protein conformation and increasing enzyme activity.

Allosteric Inhibitor

A substance that binds to an allosteric site, stabilizing the inactive form of the enzyme.

Induced-Fit Model

The change in shape of an enzyme's active site to better accommodate the substrate, enhancing catalysis.

Optimal Temperature

The temperature at which an enzyme exhibits maximum activity; enzymes have reduced activity above and below this temperature.

Optimal pH

The pH at which an enzyme exhibits maximum activity; enzymes have reduced activity at more acidic or alkaline pH levels.

Enzyme Catalyst

Cells use this to reduce the activation energy (EA) for a reaction to proceed.

Substrate

The reactant on which an enzyme acts when it catalyzes a chemical reaction; binds to the enzyme's active site.

Active Site

The specific region of an enzyme where the substrate binds and catalysis occurs.

Enzyme-Substrate Complex

The intermediate structure formed when the substrate is bound to the enzyme's active site.

Catalyst

A substance that speeds up a chemical reaction without being consumed in the process.

Activation Energy (EA)

The energy barrier that must be overcome for a reaction to take place.

Enzymes and Activation Energy

Enzymes lower the activation energy required for a reaction to proceed, speeding up the reaction.