Lab 5 - Enzymes
Niki Evans・13 minutes read
Enzymes are protein catalysts that speed up chemical reactions by lowering activation energy, with substrate-specificity and unique 3D shapes determining their function. Factors like pH, temperature, and enzyme concentration affect enzymatic activity, as seen in experiments testing how amylase digests starch under different conditions in well plates with iodine.
Insights
- Enzymes are protein-based catalysts that speed up chemical reactions by lowering activation energy. They are substrate-specific, named after the substrate they act on, and have unique 3D shapes determining their function.
- Enzymatic reactions can be influenced by various factors like pH, temperature, and substrate concentration. Denaturation of proteins, like albumin in egg whites, can impact enzyme activity. Testing enzyme activity using well plates with iodine to detect starch digestion time can reveal the effects of enzyme concentration, pH, and temperature on amylase function.
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Recent questions
What are enzymes made of?
Proteins
How do enzymes increase reaction rates?
Lower activation energy
What are cofactors in enzymes?
Non-protein portions
How do enzymes interact with substrates?
Specific active sites
What influences enzymatic activity?
pH, temperature, concentration
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Summary
00:00
Enzymes: Catalysts with Specific Functions and Inhibitions
- Enzymes are mainly composed of proteins and function as catalysts to increase the rate of chemical reactions by lowering activation energy.
- Enzymes are substrate-specific, acting on one specific substrate, such as amylase acting on starch and sucrase acting on sucrose.
- Enzymes are often named after the substrate they work on and typically end in the suffix "-ase."
- Enzymes also have non-protein portions called cofactors or coenzymes, crucial for proper enzymatic function.
- Enzymes do not change in a chemical reaction; they facilitate reactions, while substrates are used or changed.
- Enzymes reduce activation energy, which is the minimum energy required for a chemical reaction to occur, speeding up reaction rates.
- Enzymes have a unique 3D shape that determines their function, with the substrate fitting into the active site of the enzyme.
- Enzymatic reactions can be inhibited through competitive or noncompetitive inhibition, affecting the binding of substrates to enzymes.
- Competitive inhibition occurs when a non-substrate molecule binds to the active site, while noncompetitive inhibition involves binding at a different site, altering enzyme structure.
- Factors influencing enzymatic activity include pH, temperature, substrate concentration, and enzyme concentration, with optimal conditions enhancing enzymatic function.
17:53
Effect of Enzyme Factors on Starch Digestion
- Proteins in egg whites, like albumin, can be denatured when their 3D structure is altered, affecting enzyme activity. To test the impact of enzyme concentration, pH, and temperature on amylase activity, use well plates with iodine to detect starch presence, observing the time it takes for amylase to digest the starch.
- Prepare amylase and starch solutions, then transfer drops into each well every 10 seconds, noting when the starch disappears. Stop the reaction if the starch remains after two full rows, indicating the amylase couldn't digest it within approximately 240 seconds.
