Prof 2, Chapter 1 Enzymes
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/48
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
49 Terms
What are enzymes?
Enzymes are biological catalysts that speed up chemical reactions in living organisms.
What do enzymes do to activation energy?
They lower the activation energy, making the reaction easier and faster.
General enzyme reaction
Substrate → Product, catalyzed by an enzyme.
Are enzymes consumed during a reaction?
No, enzymes are not consumed and can be reused.
What is enzyme specificity?
Enzymes usually bind only one or a few specific substrates.
Example of enzyme specificity
Arginase acts on L-arginine.
What does chymotrypsin do?
It breaks peptide bonds in proteins, especially after aromatic amino acids like tyrosine and phenylalanine.
What are enzymes mainly made of?
Mostly proteins.
What are simple enzyme proteins?
Enzymes composed only of amino acids.
What are conjugated enzyme proteins?
Enzymes composed of a protein part plus a non-protein prosthetic group.
What are endoenzymes?
Enzymes that act at the place where they are synthesized.
What are exoenzymes?
Enzymes produced in one place but acting in another place.
Example of an exoenzyme
Amylase, which breaks down starch.
What are isoenzymes?
Enzymes that catalyze the same reaction but have different physical and chemical properties.
What is the active site?
The specific part of an enzyme where the substrate binds.
Lock and key hypothesis
The enzyme active site is perfectly shaped for the substrate, like a key fits a lock.
Induced fit hypothesis
The enzyme slightly changes shape to fit the substrate more precisely.
Contact amino acids in the active site
They help bind the substrate.
Catalytic amino acids in the active site
They directly participate in the chemical reaction.
Structural amino acids in enzymes
They maintain the 3D shape and stability of the enzyme.
Accepted enzyme reaction theory
The theory of intermediate complex, also called Michaelis-Menten theory.
Phase 1 of enzyme reaction
Formation of the enzyme-substrate complex.
Phase 2 of enzyme reaction
Product formation and enzyme release.
Enzyme-substrate reaction formula
E + S ⇄ ES ⇄ ES’ ⇄ E + P.
Main factors affecting enzyme reaction rate
Temperature, pH, enzyme concentration, substrate concentration, activators, and inhibitors.
What is Q10?
The temperature coefficient: change in reaction speed when temperature increases by 10°C.
Effect of increasing temperature on enzyme reaction
Reaction rate increases up to an optimum temperature.
What happens above optimum temperature?
The enzyme denatures and reaction rate decreases.
What is optimum pH?
The pH at which an enzyme works with the highest rate.
Effect of strong acid or alkali on enzymes
Most enzymes denature irreversibly.
Effect of enzyme concentration
With enough substrate, initial reaction rate is directly proportional to enzyme concentration.
More enzyme means
More active sites and faster reaction.
Effect of low substrate concentration
Reaction rate increases quickly as substrate concentration increases.
Effect of high substrate concentration
Enzymes become saturated and reaction reaches Vmax.
Vmax
The maximum rate of an enzymatic reaction.
Km
The substrate concentration at which reaction rate is half of Vmax.
What does Km indicate?
How strongly the enzyme binds the substrate.
Low Km
High enzyme affinity for substrate.
High Km
Low enzyme affinity for substrate.
What are activators?
Substances that increase enzyme activity.
Common enzyme activators
Metal ions such as Mg2+, Ca2+, Cu2+, and Zn2+.
What are inhibitors?
Substances that decrease enzyme activity.
Reversible inhibition
Inhibition where the enzyme can recover activity after inhibitor removal.
Irreversible inhibition
Inhibitor permanently blocks the enzyme, usually at the active site.
Competitive inhibition
Inhibitor resembles substrate and competes for the active site.
Non-competitive inhibition
Inhibitor binds outside the active site and reduces enzyme activity.
Acompetitive inhibition
Inhibitor binds only to the enzyme-substrate complex.
Allosteric inhibition
Inhibitor binds to an allosteric site and reduces enzyme activity.
Why is allosteric inhibition important?
It helps regulate the amount of products in the body and prevents accumulation.