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Berg JM, Tymoczko JL, Stryer L. Biochemistry. 5th edition. New York: W H Freeman; 2002.

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Biochemistry. 5th edition.

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Chapter 8Enzymes: Basic Concepts and Kinetics

The activity of an enzyme is responsible for the glow of the luminescent jellyfish at left.

Figure

The activity of an enzyme is responsible for the glow of the luminescent jellyfish at left. The enzyme aequorin catalyzes the oxidation of a compound by oxygen in the presence of calcium to release CO2 and light. [(Left) Fred Bavendam/Peter Arnold.] (more...)

Enzymes, the catalysts of biological systems, are remarkable molecular devices that determine the patterns of chemical transformations. They also mediate the transformation of one form of energy into another. The most striking characteristics of enzymes are their catalytic power and specificity. Catalysis takes place at a particular site on the enzyme called the active site. Nearly all known enzymes are proteins. However, proteins do not have an absolute monopoly on catalysis; the discovery of catalytically active RNA molecules provides compelling evidence that RNA was an early biocatalyst (Section 2.2.2).

Proteins as a class of macromolecules are highly effective catalysts for an enormous diversity of chemical reactions because of their capacity to specifically bind a very wide range of molecules. By utilizing the full repertoire of intermolecular forces, enzymes bring substrates together in an optimal orientation, the prelude to making and breaking chemical bonds. They catalyze reactions by stabilizing transition states, the highest-energy species in reaction pathways. By selectively stabilizing a transition state, an enzyme determines which one of several potential chemical reactions actually takes place.

  • 8.1. Enzymes Are Powerful and Highly Specific Catalysts
  • 8.2. Free Energy Is a Useful Thermodynamic Function for Understanding Enzymes
  • 8.3. Enzymes Accelerate Reactions by Facilitating the Formation of the Transition State
  • 8.4. The Michaelis-Menten Model Accounts for the Kinetic Properties of Many Enzymes
  • 8.5. Enzymes Can Be Inhibited by Specific Molecules
  • 8.6. Vitamins Are Often Precursors to Coenzymes
  • Summary
  • Appendix: Vmax and KM Can Be Determined by Double-Reciprocal Plots
  • Problems
  • Selected Readings

By agreement with the publisher, this book is accessible by the search feature, but cannot be browsed.

Copyright © 2002, W. H. Freeman and Company.
Bookshelf ID: NBK21166

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