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Enzyme Inhibition (26.4) Inhibition is a term used to describe the inability of a product being formed due to the presence of another substance (the inhibitor) – Enzyme inhibition can be competitive or noncompetitive Enzyme inhibition Competitive inhibition is caused when an inhibitor “competes” with the substrate in binding with the enzyme – Inhibitor decreases production of ES, thus decreasing product formation Noncompetitive inhibition is caused when an inhibitor can bind to either the free enzyme or the enzyme-substrate complex – Inhibitor does not allow ES complex to convert to products
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Enzyme Inhibition – Competitive (26.4) Competitive inhibition does not affect the maximum rate of the catalytic process, but does slow down the process Competitive inhibition – Competitive inhibition can be eliminated by increasing the substrate concentration – Preequilibrium approximation is used to eliminate [ES] and [EI] Lineweaver-Burk plots can be used to distinguish inhibition Lineweaver-Burk plots – For competitive inhibition, the maximum rate is unchanged (y-intercept is not dependent on [I]) – The effective Michaelis constant (K m *) is dependent on inhibitor concentration – For different concentrations of inhibitor, LB plots give lines with different slopes
![Enzyme Inhibition – Competitive (26.4) Competitive inhibition does not affect the maximum rate of the catalytic process, but does slow down the process Competitive inhibition – Competitive inhibition can be eliminated by increasing the substrate concentration – Preequilibrium approximation is used to eliminate [ES] and [EI] Lineweaver-Burk plots can be used to distinguish inhibition Lineweaver-Burk plots – For competitive inhibition, the maximum rate is unchanged (y-intercept is not dependent on [I]) – The effective Michaelis constant (K m *) is dependent on inhibitor concentration – For different concentrations of inhibitor, LB plots give lines with different slopes](http://images.slideplayer.com./32/9819378/slides/slide_2.jpg "Enzyme Inhibition – Competitive (26.4) Competitive inhibition does not affect the maximum rate of the catalytic process, but does slow down the process Competitive inhibition – Competitive inhibition can be eliminated by increasing the substrate concentration – Preequilibrium approximation is used to eliminate [ES] and [EI] Lineweaver-Burk plots can be used to distinguish inhibition Lineweaver-Burk plots – For competitive inhibition, the maximum rate is unchanged (y-intercept is not dependent on [I]) – The effective Michaelis constant (K m *) is dependent on inhibitor concentration – For different concentrations of inhibitor, LB plots give lines with different slopes")
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Enzyme Inhibition – Noncompetitive (26.4) Noncompetitive inhibition does affect the maximum rate of the catalytic process, but does not affect the binding of substrate to the enzyme Noncompetitive inhibition – Noncompetitive inhibition cannot be eliminated by adding more substrate (R max depends on inhibitor concentration) – Preequilibrium approximation is used to eliminate [ES], [EI], and [ESI] Lineweaver-Burk plots can be used to distinguish noncompetitive inhibition from competitive Lineweaver-Burk – For noncompetitive inhibition, the maximum rate is changed (y-intercept is dependent on [I]) – The Michaelis constant is the same as that of the uninhibited case (slope of line is not the same however, why?)
![Enzyme Inhibition – Noncompetitive (26.4) Noncompetitive inhibition does affect the maximum rate of the catalytic process, but does not affect the binding of substrate to the enzyme Noncompetitive inhibition – Noncompetitive inhibition cannot be eliminated by adding more substrate (R max depends on inhibitor concentration) – Preequilibrium approximation is used to eliminate [ES], [EI], and [ESI] Lineweaver-Burk plots can be used to distinguish noncompetitive inhibition from competitive Lineweaver-Burk – For noncompetitive inhibition, the maximum rate is changed (y-intercept is dependent on [I]) – The Michaelis constant is the same as that of the uninhibited case (slope of line is not the same however, why )](http://images.slideplayer.com./32/9819378/slides/slide_3.jpg "Enzyme Inhibition – Noncompetitive (26.4) Noncompetitive inhibition does affect the maximum rate of the catalytic process, but does not affect the binding of substrate to the enzyme Noncompetitive inhibition – Noncompetitive inhibition cannot be eliminated by adding more substrate (R max depends on inhibitor concentration) – Preequilibrium approximation is used to eliminate [ES], [EI], and [ESI] Lineweaver-Burk plots can be used to distinguish noncompetitive inhibition from competitive Lineweaver-Burk – For noncompetitive inhibition, the maximum rate is changed (y-intercept is dependent on [I]) – The Michaelis constant is the same as that of the uninhibited case (slope of line is not the same however, why )")
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Enzyme Inhibition
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Competitive Inhibition
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Noncompetitive Inhibition
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