What is an enzyme?
Biological catalysts, primarily proteins that speed up chemical reactions within cells.
What is vitalism? (The old way of looking at biochemical reactions)
The belief that living things are fundamentally different from non living things; that they contain some non physical element and are governed by different principles that inanimate objects.
Are all enzymes proteins
Yes
Are all proteins enzymes
No
A coenzyme or cofactor that is tightly associated with the enzyme is called…
A prosthetic group
(The difference is the degree of association)
3 points about catalysts
Catalysts…
1.Lower the amount of energy required for a reaction to proceed.
2.Speed up attainment of equilibrium, but do not change equilibrium.
3.Are unchanged by the reaction; they are recycled to participate in another reaction.
What are the 4 major differences between enzymes vs chemical catalysts?
- Speed: Enzymes are often much faster than chemical catalysts
- Condition: Many chemical catalysts that require extremes of temperature, presssure, and PH while enzymes function under physiological conditions
- Specificity: Enzymes have a higher degree of specificity than most chemical catalysts. This includes specificity for both what they act upon and what they produce.
- Regulation: Unlike chemical catalysts, many enzymes are responsive to the dynamic needs of the cell and organism.
What is the Circee effect in enzymes?
Some enzymes can go faster than catalytic perfection. Enzymes draw substrates towards them with charge.
Are enzymes, substrates, and products a reversible process in equilibrium
yes.
If the product has lower free energy than the substrate, its formation will be…
Spontaneous (It will occur without the input of energy)
What are the 5 points on free energy in rates and equilibrium?
1) A reaction is spontaneous only in change in free energy is negative.
2) A reaction cannot take place spontaneously if the change in free energy is positive
3) In a system at equilibrium, there is no net charge in the concentrations of the products and reactants, the change is zero.
4) Change in free energy in a reaction depends only on the free energy of the product minus the free energy of the reactants.
5) Change in free energy provides no information about the rate of the reaction.
Enzymes provide an alternate, lower-energy pathway between the substrate and the product, lowering what?
It lowers the free energy.
Do enzymes influence the difference in free energy between substrate and product?
No.
Catalytic capabilities result from both chemical and binding effects. Give an example of these effects.
Chemical: Acid/Base catalysis, Covalent catalysis
Binding: Substrate binding, transition state stabilization
Substrate binding promotes reactions by:
- Reducing entropy
- Alignment of reactive functional groups of the enzyme with the substrate.
- Desolvation of the substrate to expose reactive groups
- Distortion of substrates
- Induced fit of the enzyme in response to substrate binding.
What balance must active sites maintain to function effectively?
Active sites must be similar enough to the substrate to ensure specificity, but different enough to promote change.
The active site of an enzyme often contains what type of amino acids?
Triprotics. (Chemically reactive sidechains)
Which amino acid is often involved in acid/base catalysis?
Histidine
what are important variables to implement during measures of enzyme velocity?
-Temperature
-Concentration
-PH
What parts of the enzyme catalyze reaction contribute to the velocity of the enzyme?
-The ES complex
-K2 of E+P
Enzymes provide a lower-energy pathway between the substrate and product, _________ the activation energy of the transition state and _________ the rate of reaction.
-decreasing
-Increasing
What is the formula for finding the velocity in an enzyme
-Change in the concentration of the product over the change in time.
K1 and K-1 represent…
Rapid, non-covalent interactions between enzyme and substrate.
K2 and K-2 represents…
Rate constant of formation of product from ES.
