Enzymes Flashcards
What are enzymes made up of?
Proteins
What type of protein are enzymes?
Globular proteins
State the roles of enzymes (3)
Reduce activation energy, speed up the reaction, break and bond molecules
Differentiate between intracellular enzymes and extracellular enzymes
Intracellular: Used in the cells (E.g. ATPase , Helicase)
Extracellular: Those secreted out of the cell (E.g. pancreatic enzymes: -> Protease, Amylase, Maltase, Lipase,)
Explain the lock and key theory
Enzymes have a specific cleft/shape that substrates must fit into to be catalyzed (complimentary shape).
Which part of the (protein) enzyme binds with the substrate?
The R-group
What complex is formed after the substrate-enzyme complex?
enzyme-product complex
Explain the induced fit theory
Enzymes slightly change shapes to fit substrates into its active site
Which 4 factors effect enzyme activity?
Temperature, pH, enzyme concentration, substrate concentration
What is the optimum temperature for enzymes?
37 degrees celcius
Explain what happens if the temperature gets too high/too low for the enzymes.
Too high: enzymes become denatured
Too low: enzymes become inactive
Explain what happens if an enzyme is brought to a pH it is not made for.
Enzymes become inactive
Explain the relation to enzymes and pH
Enzymes have an optimum pH and work efficiently only in a narrow range (of pH). If brought out of it, it becomes inactive.
Which protein structures are enzymes? (primary - quartenary)
Tertiary structures (globular)
Why does the enzyme concentration graph become saturated?
If all enzyme active sites are occupied by a substrate (assuming its the limiting factor), adding enzymes won’t increase the rate of reaction, and saturation will occur.
Why does the substrate concentration graph become saturated?
Adding more substrates when all active sites of enzymes are occupied makes no difference, resulting in saturation as a further increase in rate of reaction is impossible.
Why does increasing the number of substrate molecules increase the number of substrate-enzyme complexes?
An increase in substrates increases the probability of substrates colliding with enzymes, causing the enzyme-substrate complex.
Define the Michaelis - Mentein constant (Km)
Concentration of substances that enables the enzyme to achieve half the maximum rate of reaction (Vmax/2)
OR.
is the substrate concentration at which an enzyme works at half of its maximum reaction rate (Vmax).
Define Vmax
Maximum rate of reaction. The enzyme is saturated with substrates
Explain affinity
The attraction/attachment between an enzyme and a substrate.
High affinity - strong attachment /attraction
Weak affinity - weak attachment/attraction
What does a lower Km mean in terms of affinity?
stronger affinity
What is the Michaelis-Mentein formula?
v0 = Vmax x [S] / Km + [S]
In the Michaelis-Mentein formula, what does each variable represent?
v0 = Initial reaction rate
Vmax = Maximum reaction rate
Km = Half of Vmax
S = substrate concentration
Define what an inhibitor is
An inhibitor is a molecule that slows down the rate of reaction of enzymes.
State and explain the 4 types of inhibitors
//Competitive inhibitors: molecules that compete with the substrate for the active site of enzymes, inhibiting the reaction by preventing substrate binding.
//Non-competitive inhibitors: molecules that bind to a site other than the active site (such as the allosteric site), causing a change in the enzyme’s shape, which can render the enzyme inactive or slow down the reaction.
//Irreversible inhibitors: molecules that permanently bind to the enzyme, often leading to denaturation, and thus completely inhibit its activity. (e.g. Penicillin and Nervous gas)
//End product inhibitors: When a reaction needs to stop producing, the accumulation of end products inhibits earlier enzymes in the pathway by binding to them. This prevents further reactions and helps regulate the overall process.
What are immobilizing enzymes?
Keeping enzymes in one place (immobilized) so they can’t move around. It helps them work better and allows for reuse in different reactions.
Typically for commercial purposes
List 4 advantages of immobilizing enzymes.
1-Not contaminated
2-More tolerant to pH
3-More tolerent to temperature
4-Bead formation protects the vulnerable parts
