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Catalyst
A substance that speeds up rate of reaction
Metabolism
Chemical reactions in the body that convert food into energy
Catabolic Reaction
Breaks one substrate into smaller products
Anabolic
Forms one product from smaller substrates
Active site of enzymes
The shape is complementary and highly specific to its substrates, so that it can bind to it
Induced-fit binding
The enzyme and substrate undergo conformational change to complement each other
Collision Theory
Chemical reactions occur when the reactants randomly collide
Enzyme-substrate specificity
The shape and chemical properties of an enzyme’s active site allow only specific substrates to bind
Denaturation
When a protein loses its 3D conformation and is unable to function as usual
The effect of temperature on enzymes
High temperatures increases enzyme activity, but extreme temperatures can denature enzymes
Which structure does temperature effect
Secondary structure - disruption of hydrogen bonds
Effect of pH on enzymes
Enzymes are more active in their optimum pH, but can denature at extreme levels
Which structure does pH effect
Tertiary structure - affects ionic bonds
Activation Energy
Invested energy for reaction to occur
How do enzymes affect activation energy
Enzymes lower activation energy of a reaction
Where are intracellular enzymes produced?
In the cytoplasm, by free ribosomes
Where are extracellular enzymes produced?
Synthesized by ribosomes attached to the ER, then released from the cell
Allosteric site
“second active site” from the enzyme changing shape
Non-competitive Inhibition
Inhibitors bind to allosteric site prevents catalysis
Competitive Inhibition
Inhibitors bind to the active site of enzymes to prevent substrates from binding
Feedback inhibition
Occurs when there is an excess of the end-product of a reaction pathway, where the product inhibits its produciton
Example of feedback Inhibition
Isoleucine inhibits Threonine to reduce its own production
Mechanism-based/irreversible Inhibition
Inhibitor permanently binds to active site of enzyme
Example of mechanism-based inhibition
Penicillin inhibits transpeptidase
