The Science of Enzymes

Summary:

This chapter on enzymes covers various learning objectives, including explaining the function and mode of action of enzymes, understanding enzyme kinetics, deducing the Michaelis-Menten constant (Km), and describing enzyme classification according to the International Union of Biochemistry (IUB). Enzymes are biological catalysts that speed up chemical reactions in the body. They are specific, operate on specific substrates, and can be intracellular or extracellular. Enzyme action involves the lock and key mechanism or the induced fit model. Factors such as temperature, pH, enzyme concentration, and substrate concentration affect the rate of enzyme-catalyzed reactions. Enzyme kinetics and the Michaelis-Menten equation are explored, along with the significance of Vmax and Km values. The chapter also discusses enzyme inhibitors, reversible and irreversible inhibition, and the role of enzyme cofactors. Enzyme applications in industries, such as biological detergents and genetic engineering, are highlighted.

Excerpt:

The Science of Enzymes

CHAPTER 3 – ENZYMES

Learning objectives

1. Explain the function and mode of action of enzymes
2. Explain the time course of an enzyme-catalysed reaction by measuring the rate of formation of product(s) or rate of disappearance of the substrate(s) as the rate of reaction;
3. Deduce the Michaelis-Menten constant (Km) from the Michaelis-Menten and Lineweaver-Burk plots
4. Explain the significance of Km and Vmax
5. Explain the effects of temperature, pH, enzyme concentration and substrate concentration on the rate of an enzyme-catalysed reaction.
6. Explain the roles of cofactors (ion activators, coenzymes and prosthetic groups) in an enzymatic reaction;
7. Explain the effects of competitive and noncompetitive inhibitions on the rate of enzyme activity of reversible inhibition
8. Relate the Lineweaver-Burk plot to the effect of inhibition on Km and Vmax values.
9. Describe enzyme classification according to the International Union of Biochemistry (IUB)
10. Explain the application of enzymes in industries

Introduction
Enzyme = biological catalyst
Speed up chemical reactions in the body
Globular proteins
Enzymes can be used over and over again
Usually end with the suffix ‘ase’
Intracellular or extracellular
Enzyme molecules are larger than the substrate
Highly specific- active site