L7 Flashcards
Why does the oxidation reaction of sucrose not proceed despite being extremely thermodynamic favorable
Sucrose is unreactive without a catalyst.
What are the 4 properties of acataly
- Does not change the equilibrium of a chemical rxn, but ACCELERATES the RATE at which EQUILIBRIUM is achieved.
- Functions by lowering the activation nrg of a chemical rxn.
- Lower temp, lower pressure, lower conc, neutral pH etc… - Is not used up in the rxn.
- Even when a catalysts forms an intermediate compounds during the reactants the catalyst is regenerated.
Write eqn of generic catalyst
A + B + C -> ABC -> AB + C
How do enzymes differ from chemical catalysts?
- Have all the same properties as chemical catalysts.
- With added specificity
a) complementarity in: stereochemistry, electrostatics, H-bonds, and shape
Enzymes are remarkable catalysts, enhancing reaction rates by up to ____ fold!
10^17
What is “a”
The ratio of the value of kcat for the enzymatic rxn and the value of k^uncat of the corresponding uncatalyzed reaction in aqueous sln under the same conditions.
How to determine if co-factor or co-enzyme or prosthetic group?
N/A
Examples of prosthetic group?
- FMN
- FAD
- Heme
- MoCo
Example of coenzymes?
Organics, bound loosely e.g.
Example of cofactors?
Fe / Zn ions
Example of cosubstrate?
NAD+
ATP
Example of inorganic factors?
Zn2+
Fe-S cluster
Define Apoenzyme
enzyme with cofactor
What is the enzyme commission #
N/A
Example:
EC 3.4.21.89
3 = hydrolase 4 = acting on a peptide bond 21 = uses a serine nucleophile 89 = specific protease
What are the 6 classes of enzymes in order of their classes
- Oxidoreductases aka dehydrogenase
- Transferases
- Hydrolases
- Hydratase
- Isomerase
- Ligase
- Draw a dehydroganese/oxidoreductase rxn.
- What does it transfer?
- What does it usually use as cofactors?
- ethanol + NAD+
- –>NAD:alcohol / dehydrogenase
- Draw a transferase rxn.
2. What does it transfer?
- Glucose + ATP
- ———> ATP:glucose/ phosphotransferrase
- Draw a hydrolases rxn.
2. Example?
- glucose-6-phosphate + H2O
- ———–> glucose-6- phosphatase
- Draw a hydrotases rxn.
2. Another name for hydratases?
- cis-aconitate + H2O
- ————-> aconitate hydratase
- Draw a isomerase rxn.
Glc-6P
————–> glc-6-phosphatase isomerase
- Draw a ligase rxn.
Pyruvate + Bicarbonate + ATP
———> pyruvate carboxylase
