Enzyme Definitions Flashcards
CATALYST
A substrate that increase the rate of a reaction, without being consumed in the reaction; includes enzymes.
ENZYME
Protein that catalyses (increases the rate of) chemical reactions in living organisms. An enzyme is specific for a particular chemical reaction and may be used over and over again.
SUBSTRATE
A substance that is acted on by a catalyst such as an enzyme.
ACTIVE SITE
The site on the surface of an enzyme that binds the substrate molecule.
ACTIVATION ENERGY
Energy required to start a chemical reaction.
OPTIMUM TEMPERATURE
Temperature at which an enzymes catalytic activity is greatest.
37 degrees Celsius for humans
CRITICAL TEMPERATURE
Temperature at which denaturation of enzyme molecules begins to occur as temperature rises.
DENATURATION
Irreversible change in protein structure, usually as a result of heating above a certain critical temperature.
AFFINITY
Measure of the ease with which an enzyme binds with its substrate.
PROTEASE
Enzymes that cut proteins into smaller polypeptides.
LIPASE
Enzyme that breaks down lipids
PRODUCT
Formation of new compound (from others)
REACTANT
Chemical elements/compounds
SPECIFICITY
- Each enzyme acts on a specific substrate only.
[Enzymes are highly specific]
Called specificity
OPTIMAL pH
-Optimal pH, enzymes can bind to the substrate, change in pH can alter of an enzyme so it can no longer bind to the substrate.
Optimal pH = enzymes maximum activity (acidity & alkalinity)
A change in ph can alter the 3-D structure of the enzyme- reduce enzyme function.
Pepsin- stomach, pH 2
Trypsin- small intestine, pH 8
Carbonic anhydrase- human blood, pH 7.4
Human cell enzyme- pH 7.6
