Enzymes and Their Functions | Chemistry for JAMB PDF Download

Enzymes and Their Functions

• Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process.
• They are usually proteins, but some RNA molecules, known as ribozymes, can also exhibit enzymatic activity.
• Enzymes play crucial roles in various metabolic processes, maintaining homeostasis, and ensuring proper functioning of cells.

Digestive Enzymes

• Proteases: Break down proteins into amino acids (e.g., pepsin, trypsin).
• Lipases: Hydrolyze fats into fatty acids and glycerol (e.g., pancreatic lipase).
• Amylases: Convert starch and glycogen into simple sugars (e.g., salivary amylase, pancreatic amylase).

Metabolic Enzymes

• Oxidoreductases: Catalyze oxidation-reduction reactions (e.g., dehydrogenases, cytochromes).
• Transferases: Transfer functional groups between molecules (e.g., kinases, transaminases).
• Isomerases: Rearrange the structure of molecules (e.g., glucose-6-phosphate isomerase).
• Ligases: Join two molecules together using ATP (e.g., DNA ligase, RNA ligase).
• Hydrolases: Break down molecules using water (e.g., phosphatases, nucleases).

Energy-Related Enzymes

• ATP synthase: Synthesizes ATP during cellular respiration.
• Hexokinase: Catalyzes the first step of glycolysis, phosphorylating glucose.
• Phosphofructokinase: Controls the rate of glycolysis by catalyzing the third step.
• Citrate synthase: Catalyzes the first step of the citric acid cycle (Krebs cycle).
• Cytochrome c oxidase: Facilitates the final step of the electron transport chain.

Regulatory Enzymes

• Allosteric enzymes: Activity is regulated by the binding of molecules at sites other than the active site.
• Feedback inhibition: The end product of a metabolic pathway inhibits an earlier enzyme in the pathway.
• Enzyme induction: Increased synthesis of an enzyme in response to a substrate or specific condition.

Industrial Enzymes

• Amylases: Used in the production of starch, detergents, and food processing.
• Proteases: Used in laundry detergents, leather processing, and meat tenderization.
• Cellulases: Break down cellulose in biofuel production and textile industry.
• Lipases: Used in baking, dairy industry, and detergent formulation.

Remember, enzymes are highly specific in their action and can be influenced by factors like temperature, pH, substrate concentration, and enzyme concentration. Understanding their functions and mechanisms is essential in various fields, including biochemistry, medicine, and biotechnology.