2.1.4 Enzymes Flashcards
What are enzymes?
Biological catalysts that can speed up the rate of a reaction in the body.
Enzymes provide…
Alternate pathways by reducing the activation energy of the reaction.
What is activation energy?
Activation energy is the minimum amount of energy needed for a reaction to start
Enzymes reduce the amount of activation energy needed; this means that…
Reactions can happen at lower temperatures
(most bodily reactions would not be possible at body temp if not for enzymes)
After a reaction enzymes remain…
Unchanged; can be reused
What are the 2 types of enzymes?
Extracellular
Intracellular
Intracellular enzymes
Found in the cell e.g. RNA Polymerase, DNA helicase etc.
Extracellular enzymes:
Found outside of cells e.g. Amylase
Enzymes are…
Globular Proteins
Globular proteins are…
Spherical (quaternary structure)
Easily soluble and can be transported easily (e.g. blood etc.)
It can denature if pH and temperature deviate from the optimum.
Enzymes have…
Active sites (with specific shapes)
The shape of the active site is complementary to …
the shape of the substrate
What is the name of the additional binding regions some enzymes have
Allosteric site (alternative site)
Allosteric sites are only occupied by mainly?
non-competitive inhibitors
What are the 2 models/theories for enzyme action?
Lock and Key model/theory
Induced fit model/theory
Lock and Key Theory:
- Substrate binds to enzyme’s active site (complementary); Enzyme-substrate complex formed
- E-P complex then forms in the enzyme’s active site
- Products are then released from the active site
Induced fit Theory:
Only occurs when the shape of the enzyme active site and substrate are not entirely complementary.
- Substrate enters the enzyme’s active site (ES complex)
- Enzymes undergo a conformational change, which allows the active site of the enzyme to be complementary to the substrate.
- This induces the formation of an EP complex
- Products are then released by the active site
