7: Enzyme Kinetics
Reaction rates, enzyme efficiency, and inhibition mechanisms.
LibreTexts reference: Enzyme Kinetics
Enzyme Inhibition and Activation in Metabolic Pathways
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A series of enzymes catalyze the reactions in the following metabolic pathway:
| enzyme 1 | enzyme 2 | enzyme 3 | enzyme 4 | |||||||||||||||
| N | ⟶ | O | ⟶ | P | ⟶ | Q | ⟶ | R | ||||||||||
Understanding the type of enzyme inhibition or activation is crucial for developing effective drugs and understanding metabolic regulation.
enzyme 1 converts substrate N into product O.The end product R of this pathway binds to enzyme 1at a location far away from its active site.
This binding decreases the activity of the enzyme.
Determine the type of enzyme inhibition or activation described:
Enzyme Catalysis Terminology
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Which one of the following terms related to enzyme catalysis correspond to the definition 'substance used to cause or facilitate a chemical reaction'.
True/False Statements on Enzyme Kinetics
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Which one of the following statements is FALSE regarding enzyme kinetics?
True/False Statements on Michaelis-Menten Kinetics
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Which one of the following statements is FALSE about Michaelis-Menten kinetics?
Which Molecule Cannot be an Enzyme Cofactors
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Michaelis-Menten Constant (KM) from Enzyme Activity Data
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Michaelis-Menten question. The following question refers to the table (below) of enzyme activity.
| substrate concentration, [S] |
initial reaction velocity V0 |
|---|---|
| 0.001 | 11.0 |
| 0.002 | 20.0 |
| 0.005 | 40.0 |
| 0.010 | 60.0 |
| 0.020 | 80.0 |
| 0.050 | 100.0 |
| 0.100 | 109.1 |
| 0.200 | 114.3 |
| 0.500 | 117.7 |
| 1.000 | 118.9 |
| 10.000 | 119.9 |
| 100.000 | 120.0 |
Using the table (above), calculate the value for the Michaelis-Menten constant, KM.
Inhibition Type Determination from Enzyme Activity Data
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Michaelis-Menten Kinetics and Inhibition Type Determination
The table below presents data on enzyme activity measured as initial reaction velocities (V0) with and without the presence of an inhibitor at various substrate concentrations ([S]).
| substrate concentration, [S] |
initial reaction velocity no inhibitor V0 (–inh) |
initial reaction velocity with inhibitor V0 (+inh) |
|---|---|---|
| 0.0001 | 30.0 | 26.7 |
| 0.0002 | 51.5 | 40.0 |
| 0.0005 | 90.0 | 57.2 |
| 0.0010 | 120.0 | 66.7 |
| 0.0020 | 144.0 | 72.8 |
| 0.0050 | 163.7 | 77.0 |
| 0.0100 | 171.5 | 78.5 |
| 0.0200 | 175.7 | 79.3 |
| 0.0500 | 178.3 | 79.7 |
| 0.1000 | 179.2 | 79.9 |
| 1.0000 | 180.0 | 80.0 |
Based on the data provided, determine the type of inhibition show by the inhibitor. Consider how the addition of the inhibitor affects the initial reaction velocities (V0) at various substrate concentrations ([S]).
Which Molecule Could be an Enzyme
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Enzymes are biological catalysts that speed up chemical reactions in living organisms.
Which one of the following choices is most likely an enzyme?
Hint: enzymes often have a distinct naming pattern that can help identify them.