Energy, Enzymes, and Catalysis Problem Set
Problem 1 Tutorial: Features of enzyme catalyzed reactions.
Features of Enzyme Catalyzed Reactions
Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy. Many enzymes change shape when substrates bind. This is termed "induced fit", meaning that the precise orientation of the enzyme required for catalytic activity can be induced by the binding of the substrate.
Enzymes have active sites. The enzyme active site is the location on the enzyme surface where substrates bind, and where the chemical reaction catalyzed by the enzyme occurs. There is a precise substrate interaction that occurs at the active site stabilized by numerous weak interactions (hydrogen bonds, electrostatic interactions, hydrophobic contacts, and van der Waals forces).
Enzymes form complexes with their substrates. The binding of a substrate to an enzyme active site is termed the "enzyme-substrate complex." A generic equation for complex formation is as follows:
Department of Biochemistry and Molecular Biophysics
University of Arizona
Revised: October 2004
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