Overview
This lecture introduces enzymes, their roles as biological catalysts, how they function, and factors that affect their activity, along with lab safety instructions for the upcoming experiment.
Enzyme Basics
- Enzymes are proteins that act as catalysts in biological systems, speeding up chemical reactions without being consumed.
- Reactants in a chemical reaction are called substrates in biology, and the outcome is called the product.
- Enzymes facilitate the assembly or breakdown of macromolecules like carbohydrates, nucleic acids, and proteins.
- Most enzyme names end with the suffix "-ase" (e.g., sucrase, lipase, maltase, lactase).
How Enzymes Work
- Enzymes have specific shapes, allowing them to interact only with particular substrates (specificity).
- The region of an enzyme that binds the substrate is called the active site or binding site.
- Enzyme-substrate binding forms a temporary complex, after which the enzyme is released to catalyze more reactions.
- Some enzymes build molecules (anabolic), while others break them down (catabolic).
Factors Affecting Enzyme Activity
- Increasing enzyme or substrate concentration generally increases reaction rate, up to a point.
- pH and temperature changes can alter enzyme structure, leading to denaturation and loss of function.
- Chemicals (like heavy metals, poisons, or soaps) and radiation can also denature enzymes.
Lab Safety and Procedures
- Always wear goggles when handling acids, bases, and hot water.
- Report broken glassware to the instructor, dispose of glass properly, and avoid cross-contamination.
- Solids go in the garbage; only liquids should be poured down the sink.
- Begin with lab procedures 2-5 due to incubation times, then complete procedure 1 during incubation.
Key Terms & Definitions
- Enzyme — Protein catalyst that speeds up biochemical reactions without being consumed.
- Catalyst — Substance that increases reaction rate but is not part of the final product.
- Substrate — The reactant(s) enzymes act on.
- Active Site — Region on the enzyme where the substrate binds.
- Specificity — Enzyme property of acting only on certain substrates.
- Denaturation — Loss of enzyme shape and function due to environmental conditions.
Action Items / Next Steps
- Wear goggles and follow all lab safety rules.
- Start procedures 2–5 first to allow for incubation times.
- Pick up any spills and properly dispose of solids and liquids.
- Read lab protocol for experiment two before class.