Chapter Three Enzymes 1 Inhibition of Enzymes Can
Chapter Three: Enzymes 1
Inhibition of Enzymes Can be irreversible (metals) or reversible (product, substrate, salt, etc. ) Types: 1. Competitive 2. Noncompetitive 3. Uncompetitive 4. Substrate Inhibition 2
Competitive Inhibition Inhibitor is an analog of the substrate, and binds to the active site of the enzyme. 3
Mechanism of Competitive Inhibition What assumption have we make in defining the parameters on the right? 4
Competitive Inhibition Product formation rate is given by: What is the magnitude of relative to and what will be the effect on v? How could you run a process to minimize the effects of this type of inhibition? 5
Competitive Inhibition I>0 1/v I=0 Vm is unchanged -1/Km, app 1/Vm 1/[S] 6
Noncompetitive Inhibition Inhibitor binds to the enzyme and/or enzyme-substrate complex, but not at the active site. However, the enzyme affinity for substrate is reduced. 7
Mechanism of Noncompetitive Inhibition 8
Noncompetitive Inhibition Product formation rate is given by: Question: What is the magnitude of Vm, app relative to Vm, and what will be the effect on v? How can you moderate the effects of this type of inhibition. 9
Noncompetitive Inhibition I>0 1/v I=0 1/Vm, app 1/Vm -1/Km Km is unchanged 1/[S] 10
Uncompetitive Inhibition Inhibitor binds only to ES complex, and not to E alone. 11
Uncompetitive Inhibition Rate is given by: What is the magnitude of Vm, app relative to Vm? What is the magnitude of relative to ? 12
Uncompetitive Inhibition 1/v I>0 I=0 1/Vm, app 1/Vm -1/Km, app -1/Km 1/[S] 13
Substrate Inhibition Substrate binds to ES complex. 14
Substrate Inhibition No substrate inhibition v Substrate inhibition S The maximum substrate concentration resulting in maximum reaction rate is: 15
Summary of Enzyme Inhibition 16
Example 3. 2
Example 3. 2
Example 3. 2
Example 3. 3
Example 3. 3
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