Lecture 7 - Enzymes are Essential for Life Flashcards
G < 0 =
Spontaneous; energy release.
G > 0 =
Non - Spontaneous; energy required
G = 0 =
At equilibrium; can’t do work.
What does biochemical synthesis and degradation use?
Pathways of enzyme catalysed steps.
What can enzymes do?
Couple a spontaneous reaction to a non spontaneous one, to make the overall G < 0
What is required to reach the transition state?
Sufficient activation energy
What are enzymes?
Biological catalysts which increase the rate of reaction by lowering the activation energy
What is the transition state?
Reaction intermediate between the substrate and product, the state corresponding to the highest potential energy,
What are the classes of enzymes?
- Oxireductases - Redox
- Trasnferases - Transfer of functional group
- Hydrolases - Hydrolysis reactions
- Lyases - Non-hydrolytic breaking or making of bonds
- Isomerases - Transfer of atoms/groups within a molecule
- Ligases - Joining of two molecules together
What are Cofactors?
Non-protein helper molecules that sit inside the active site and essential for reaction to occur
What are the two classes of cofactors?
Metal ions and Coenzymes
What are metal ions?
Lewis acids, so they can participate in acid-base catalysis.
What do metal ions do?
Form coordination compounds with precise geometries. (Position reactants exactly where they need to be)
What are coenzymes?
Small organic molecules that are carriers, (electrons, atoms and functional groups), often derived from vitamins.
What do enzymes allow?
Reaction coupling
