key term - Enzyme Catalysis

Definition

Enzyme catalysis is the process by which enzymes, which are biological catalysts, accelerate the rate of chemical reactions in living organisms. Enzymes achieve this by lowering the activation energy required for a reaction to occur, allowing it to proceed more rapidly under physiological conditions.

5 Must Know Facts For Your Next Test

1. Enzymes can increase the rate of a reaction by a factor of millions compared to the uncatalyzed reaction.
2. Enzymes achieve catalysis by providing an alternative reaction pathway with a lower activation energy barrier.
3. The active site of an enzyme is complementary in shape and charge to the substrate, facilitating binding and catalysis.
4. Enzyme catalysis is reversible, and the rate of the forward and reverse reactions can be regulated by factors such as substrate concentration, product inhibition, and allosteric modulation.
5. Enzyme catalysis is essential for the efficient operation of numerous biological processes, including metabolism, DNA replication, and signal transduction.

Review Questions

• Explain how enzyme catalysis is involved in the biological addition of radicals to alkenes (Topic 8.11).
  • Enzyme catalysis plays a crucial role in the biological addition of radicals to alkenes, which is a common reaction in living organisms. Enzymes can catalyze the addition of radicals, such as hydrogen or halogen radicals, to alkenes by lowering the activation energy barrier and facilitating the formation of the transition state. This allows the reaction to proceed more rapidly under physiological conditions, enabling essential biological processes like the biosynthesis of complex organic molecules.
• Describe the importance of enzyme catalysis in biological substitution reactions (Topic 11.6).
  • Enzyme catalysis is essential for the efficient operation of biological substitution reactions, which involve the replacement of one functional group or atom with another. Enzymes can catalyze these reactions by providing an alternative reaction pathway with a lower activation energy, allowing the substitution to occur more readily under the mild conditions found in living organisms. This is crucial for a wide range of biological processes, such as the metabolism of drugs and xenobiotics, the biosynthesis of natural products, and the modification of proteins and other biomolecules.
• Analyze how enzyme catalysis contributes to the chemistry of thioesters and acyl phosphates, which are important biological carboxylic acid derivatives (Topic 21.8).
  • Enzyme catalysis is central to the chemistry of thioesters and acyl phosphates, which are crucial biological carboxylic acid derivatives. Enzymes can catalyze the formation and cleavage of these high-energy compounds, which are involved in a variety of metabolic pathways, including energy production, lipid synthesis, and protein modification. By lowering the activation energy barriers, enzymes facilitate the rapid and efficient interconversion of these important biological species, enabling the precise regulation of cellular processes and the efficient utilization of chemical energy within living organisms.

Related terms

Active Site:

The specific region on an enzyme where the substrate binds and the catalytic reaction takes place.

Substrate:

The molecule or molecules upon which an enzyme acts, undergoing a chemical transformation.

Catalytic Efficiency:

The measure of how effectively an enzyme can catalyze a reaction, typically expressed as the ratio of the reaction rate to the enzyme concentration.