enzyme kinetics lecture

Computational Systems Biology

Computational Systems Biology

Lecture 3: Enzyme kinetics
Tue 17 Jan 2006 with the collaboration of Luna De Ferrari

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Images from:
D. L. Nelson, Lehninger Principles of Biochemistry, IV Edition, W. H. Freeman ed.
A. Cornish-Bowden Fundamentals of Enzyme Kinetics, Portland Press, 2004
A. Cornish-Bowden Enzyme Kinetics, IRL Press, 1988

Computational Systems Biology

Summary:
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Simple enzyme kinetics
Steady-state rate equations
Reactions of two substrates
Inhibition of enzyme activity pH dependence
Biological regulation of enzymes

Computational Systems Biology

Simple Enzyme Kinetics

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Computational Systems Biology

Basics
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An essential feature of enzyme-catalyzed reactions is saturation: at increasing concentrations of substrates the rate increases and approaches a limit where there is no dependence of rate on concentration (see slide with limiting rate Vmax)

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Leonor Michaelis and Maud Menten were among the first scientist to experiment with enzyme kinetics in a “modern” way, controlling the pH of the solution etc.

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Enzyme kinetics studies the reaction rates of enzyme-catalyzed reactions and how the rates are affected by changes in experimental conditions The convention used for this slides is to use UPPERCASE for the molecular entity: e.g. E is an enzyme molecule and italics lowercase for the concentration: e.g. e0 is the enzyme concentration at time zero
(initial concentration). Also square brackets can be used for concentration, e.g. [E] = enzyme concentration.
For additional material: Fundamentals of Enzyme Kinetics, Athel Cornish-Bowden, 2004 or
Enzyme Kinetics, Athel Cornish-Bowden and C. W. Wharton, IRL Press, 1988

Computational Systems Biology

A simple view:
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E+A = EA as an equilibrium

The mechanism: the first step of the reaction is the binding of the substrate
(A) to the enzyme (E) to form and