Recording-2025-03-03T19:03:50.033Z

Activation Energy

• Definition: The minimum energy required for a chemical reaction to occur.

• Importance: All chemical reactions need a certain amount of energy input to proceed from reactants to products.

• Consequences of No Activation Energy: Without activation energy as a barrier, every possible reaction would happen instantly, leading to chaos in the universe.

Role of Enzymes in Lowering Activation Energy

• Function: Enzymes lower the activation energy, speeding up reactions.

• Microenvironments: Enzymes create specific environments that significantly increase the reaction rates, enabling reactions that would otherwise be incredibly slow (e.g. happening once every ten thousand years could occur in a fraction of a second).

• Mechanism: Enzymes change their shape to accommodate substrates, forming an enzyme-substrate complex.

Enzyme-Substrate Complex

• Induced Fit Model: When a substrate binds to an enzyme, it alters the shape of the enzymes active site to achieve a better fit.

  • Example: Using Pacman as a metaphor for an enzyme, where the mouth represents the active site.

• Types of Bonds: The interactions within the enzyme-substrate complex can involve hydrogen bonds, covalent bonds, or ionic bonds.

• Product Formation: Upon forming the complex, the substrate is altered and converted into products, which are released, allowing the enzyme to return to its original shape.

Types of Reactions

Catabolism

• Definition: The breakdown of larger molecules into smaller molecules, releasing energy.

• Example: Enzymatic digestion of a disaccharide (sucrose) into two monosaccharides.

Anabolism

• Definition: The synthesis of larger molecules from smaller ones, requiring energy input.

• Reversibility: Enzymes can sometimes facilitate both catabolic and anabolic reactions, but focus is mainly on catabolic reactions in the context of this discussion.

Importance of Enzymes

• Real-World Examples:

  • Laundry Detergents: Enzymes (like proteases and lipases) digest lipids and proteins in stains, making them easier to wash out.

  • Dishwashing Detergents: Contain enzymes that break down food residues, effective under hot water conditions.

• Cooking and Meat Tenderization: Enzymes such as bromelain (from pineapple) and papain (from papaya) are used to tenderize meat by partially digesting it before cooking.

Enzyme Stability and Limitations

• Denaturation: Enzyme activity can diminish with extreme heat or pH changes, altering their shape and functionality.

• Enzymes in Nature: Many enzymes can only function under specific conditions and may become inactive due to the harsh environment of the stomach when they are ingested.

Fresh vs. Canned Pineapple in Cooking

• Bromelain Effect: Fresh pineapple contains bromelain, which prevents gel formation in Jell-O by digesting the gelatin protein. Canned pineapple is safe for use after heating denatures the enzyme.

Practical Tips for Enzyme Efficiency

• Dishwasher Use:

  • Start hot water before running the dishwasher to ensure enzymes are active from the beginning.

  • Use additional powdered detergent for optimal performance.

• Health Considerations: While some enzymes are marketed for health benefits, many dissolve in the digestive process, losing their efficacy for medicinal uses.