Basic Concepts of Enzyme Action

97

  • 6.1 Enzymes Are Powerful and Highly Specific Catalysts

  • 6.2 Many Enzymes Require Cofactors for Activity

  • 6.3 Gibbs Free Energy Is a Useful Thermodynamic Function for Understanding Enzymes

  • 6.4 Enzymes Facilitate the Formation of the Transition State

The activity of an enzyme is responsible for the glow of the luminescent jellyfish. The enzyme aequorin catalyzes the oxidation of a compound by oxygen in the presence of calcium to release CO2 and light.

The energy and information processing that takes place inside a cell consists of thousands of individual chemical reactions. For these reactions to take place in a physiologically useful fashion, they must occur at a rate that meets the cell’s needs, and they must display specificity; that is, a particular reactant should always yield a particular product. Side reactions leading to the formation of useless or hazardous by-products must be minimized. In this chapter, we consider the key properties of enzymes, with a special look at the energetics of enzyme-catalyzed reactions.