Globular proteins that catalyze reactions inside cells (intracellular enzymes) or are secreted to catalyse reactions outside cells (extracellular enzymes)

Lowers activation energy and provides an alternative reaction pathway; Specifically shaped active site -> temporary enzyme-substrate complex

What changes determine the shape?

Order of amino acids changes 3D shape

Breaking of complex molecules into simpler products - cellular respiration and hydrolysis

Building complex molecules from simpler products -Protein synthesis and photosynthesis

Induced fit hypothesis?

Substrate induces a small, temporary, confirmational change in the shape of the active site that makes it complimentary in shape to the substrate

Enzyme substrate complex

Substrate interacts with catalytic amino acid R grps (temporary bonds). Active site changes shape to bind strongly

Experiments to measure enzyme activity

Catalase H2O2 breakdown - collect gas/count bubbles Test Amylase action on starch with iodine (vary Ph/ temp) Colorimeter - light absorbance

Factors affect enzyme action

Substrate, enzyme concentration, pH, Temp, Inhibitor conc

Vmax = Max rate of enzyme reaction. Km = substrate conc at half Vmax

Why are Km and affinity inversely proportional?

Low Affinity, higher Km as more Substrate needed to reach 1/2 Vmax - fewer ESCs in same unit time - AS less good fit

Effect of pH on enzyme action

High conc of H+/ OH- cause H and Ionic bonds to break, AS changes shape and S can't bind to tertiary structure of protein

Competitive inhibitor action

Competes with S for AS - reversible by increasing S conc.

Non-competitive inhibitors action

Irreversible - binds to an ALT site on enzyme and disrupts hydrophobic and H bonds - distorts E and AS shape

Competitive effects vs non-competitive effects

Vmax stays same - determined by enzyme only; Km increases - more S needed to reach 1/2 Vmax. Slower increase of ROR. Non - Vmax decreased - lower available E, Km constant

End product inhibition purpose

Maintains homeostasis, controls metabolic reactions

Non-competitive, reversible inhibitor

End product binds to ALT site of E and inhibits further product formation (distorts AS shape) then detaches when product conc. drops and AS is return to active state-> continuous feedback loop

Lactase coated in Alginate beads (inert, insoluble)

Advantage of immobilized enzymes

Purer product (no filter), greater tolerance to pH and temp changes, can be reused (cost effective)

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Enzymes

Action, Functions, Factors that affect enzymes

Question	Answer
What is an enzyme?	Globular proteins that catalyze reactions inside cells (intracellular enzymes) or are secreted to catalyse reactions outside cells (extracellular enzymes)
Mode of action	Lowers activation energy and provides an alternative reaction pathway; Specifically shaped active site -> temporary enzyme-substrate complex
What changes determine the shape?	Order of amino acids changes 3D shape
Catabolic	Breaking of complex molecules into simpler products - cellular respiration and hydrolysis
Anabolic	Building complex molecules from simpler products -Protein synthesis and photosynthesis
Induced fit hypothesis?	Substrate induces a small, temporary, confirmational change in the shape of the active site that makes it complimentary in shape to the substrate
Enzyme substrate complex	Substrate interacts with catalytic amino acid R grps (temporary bonds). Active site changes shape to bind strongly
Experiments to measure enzyme activity	Catalase H2O2 breakdown - collect gas/count bubbles Test Amylase action on starch with iodine (vary Ph/ temp) Colorimeter - light absorbance
Factors affect enzyme action	Substrate, enzyme concentration, pH, Temp, Inhibitor conc
Vmax and Km	Vmax = Max rate of enzyme reaction. Km = substrate conc at half Vmax
Why are Km and affinity inversely proportional?	Low Affinity, higher Km as more Substrate needed to reach 1/2 Vmax - fewer ESCs in same unit time - AS less good fit
Effect of pH on enzyme action	High conc of H+/ OH- cause H and Ionic bonds to break, AS changes shape and S can't bind to tertiary structure of protein
Competitive inhibitor action	Competes with S for AS - reversible by increasing S conc.
Non-competitive inhibitors action	Irreversible - binds to an ALT site on enzyme and disrupts hydrophobic and H bonds - distorts E and AS shape
Competitive effects vs non-competitive effects	Vmax stays same - determined by enzyme only; Km increases - more S needed to reach 1/2 Vmax. Slower increase of ROR. Non - Vmax decreased - lower available E, Km constant
End product inhibition purpose	Maintains homeostasis, controls metabolic reactions
Non-competitive, reversible inhibitor	End product binds to ALT site of E and inhibits further product formation (distorts AS shape) then detaches when product conc. drops and AS is return to active state-> continuous feedback loop
Immobilized enzyme	Lactase coated in Alginate beads (inert, insoluble)
Advantage of immobilized enzymes	Purer product (no filter), greater tolerance to pH and temp changes, can be reused (cost effective)

Created by: user-1992837

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