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Flashcards in Enzyme Kinetics Deck (15)
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1
Q

2 Mechs of Enzymes Decreasing DeltaG (and kind of effect each is)

A

Ground state destabilization (DeltaH effect)

Transition state stabilization (DeltaS effect)

2
Q

4 Mechs of Catalysis (and 1 major point)

A
General Acid/Base Catalysis
Electrostatic catalysis
Covalent catalysis
Entropy
- All chemical rxns entail charge redistribution
3
Q

2 Properties of Enzyme Active Sites

A

Invaginated pocket to position things close, DeltaS effect

Microenvironment affects ionization status (pKa) of enzyme and substrate groups

4
Q

2 Reasons Why Initial Velocity Must be Taken Immediately

A
  1. [A] is well approximated by [A]i

2. Amount of [P] is negligible and won’t interfere

5
Q

Requirement for Continuous Assays (2)

A

Ability to measure either disappearance of substrate or appearance of product

6
Q

“Coupled” Continuous Assays (2)

A

For when substrate-products have no spectroscopic properties - couple a given product to a rxn that does yield spectroscopic properties

7
Q

Discontinuous Assay (reason & method)

A

When substrate-product exhibits similar/no spectroscopic properties
Radiolabel substrate, quench the rxn at different times, wash away radiolabeled substrate and measure product

8
Q

kcat

A

Turnover number, maximum number of substrate molecules converted to product per unit time

9
Q

Km

A

Michaelis constant, substrate concentration [A] that yields 1/2 Vmax

10
Q

kcat/Km

A

Specificity constant

11
Q

2 Conclusions of Competitive Inhibitors

A

kcat independent of [I[

Km increases linear w/ [I]

12
Q

2 Conclusions of Uncompetitive Inhibition

A

kcat decreases hyperbolic w/ [I]

Km decreases hyperbolic w/ [I]

13
Q

2 Conclusions of Noncompetitive Inhibition

A

kcat decreases hyperbolic w/ [I]

Km independent of [I]

14
Q

Conclusion of Enzyme w/ Multiple Active Sites w/ No Cooperativity

A

Impossible to kinetically distinguish b/w 1 mole of enzyme w/ n identical sites and n moles of enzyme with a single site

15
Q

Main Conclusion of Enzymes w/ Multiple Active Sites w/ Positive Cooperativity

A

Provides enhanced sensitivity to changes in [A] in narrow physiological range (S-shaped curve)