Biochemistry E2 Flashcards

1
Q

What is the fractional saturation of binding?

A

Y= [S] ÷ (KD + [S])

The concentration of bound ligand divided by the total amount of protein/enzyme

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2
Q

What is KD

A

The dissociation constant or the [S] at half the saturation

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3
Q

What is KD related to when the protein is enzymatic/catalytic?

A

KD=KM

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4
Q

In a Sctchard plot graph, when n=1,
Slope
x-intercept
y-intercept

A

Slope: -1/KD
x-intercept = [E]T
y-intercept = 1/KD

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5
Q

In a Sctchard plot graph, when n>1,
Slope
x-intercept
y-intercept

A

Slope: -1/KD
x-intercept = n
y-intercept = n/KD

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6
Q

What is the Hill Equation?

A

Log(ø ÷ (1-ø)) = Log (1/KD) + nLog[S]

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7
Q

What type of graphs are Hill Plots usually?

A

Sigmoidal

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8
Q

What does the slope of the Hill plot tell us?

A

Slope= n
n>1 = Positive cooperativity
0

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9
Q

What is the y-intercept of the Hill plot?

A

log(1/KD) = log(1/Km)

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10
Q

Michaelis-Menten Kinetics follow what order of enzymes?

A

First Order Enzymes

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11
Q

What does the graph of Zero-order kinetics look like?

A

If [S] vs time is linear, the reaction is 0-order

v=k

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12
Q

What does the graph of First-order kinetics look like?

A

If ln[S] vs time is linear, the reaction is 1st order

v=k[S]

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13
Q

What does the graph of Second-order kinetics look like?

A

If 1/[S] vs time is linear, the reaction is 2nd order

v=k[S][S] or v=k[S1][S2]

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14
Q

What is the initial reaction rate equation?

A

V0 = Vmax • [S] ÷ ([S] + Ks)

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15
Q

What are the three assumptions for Michaelis-Menten Kinetics?

A
  1. Binding of the substrate to the enzyme is at equilibrium
    (Ks = K-1/K1)
  2. Since we are measuring initial rate, not enough product is present for the reverse reaction to occur
    (Secon step is irreversible)
  3. Stead State Assumption
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16
Q

What is the steady state assumption?

A
  • When [S] is very large, ∆[S] = 0

- Formation of E•S complex occurs at the same rate that its loss either by dissociation or by product formation

17
Q

Define Km

A

Michaelis Menten constant
When [S] where half the active sites are full
OR
When [S] where the reaction is half maximal

18
Q

What is the equation for the Michaelis Menten Kinetics?

A

V0= Vmax • [S] ÷ ([S]+Km)

19
Q

Define Vmax

A

How fast the reaction can take place

Vmax = Kcat[E]

20
Q

Kcat is the same as

A

K2
Movement from E•S complex to E•P complex
(Changing Substrate to Product)

21
Q

What happens when [S]<

A

V0 = (vmax÷Km) * [S]

Less than half the binding sites are occupied

22
Q

What happens when [S]=Km

A

V0 = Vmax/2

Half the binding sites are occupied

23
Q

What happens when [S]»Km

A

V0 = Vmax

All the binding sites are occupied

24
Q

What is the specificity constant?

A

Kcat ÷ Km = (Kcat ÷ (K-1 +Kcat)) •K1
Used to determine catalytic efficiency
Measures what happens when to E•S complex

25
A good enzyme vs a poor enzyme
Good enzymes: Kcat>>K-1 (More production of product) Poor Enzymes: Kcat<
26
Lineweaver-burk plots are used for
reversible inhibitors
27
What is vmax and Km with a competitive inhibitor?
Vmax is constant and Km is variable Inhibitor binds at the enzyme
28
What is vmax and Km with a Noncompetitive inhibitor?
Vmax is variable and Km is constant Inhibitor binds at Enzyme or E•S complex
29
What is vmax and Km with an uncompetitive inhibitor?
Vmax is variable and Km is variable Binds at E•S complex
30
Constitutional Isomers
Changes orders of atoms | Also called Tautomers
31
Stereoisomers have the
same connectivity, but different spatial organization
32
Configurational Isomers are
Stereoisomers that have chiral carbons
33
Enantiomers are
mirror images at ALL CHIRAL centers
34
Diastereomers have
multiple chiral centers, but not all chiral centers are mirror images
35
The anomeric carbon decides
Whether it is an alpha or beta carbohydrate in the ring form Beta is up Alpha is down
36
When converting from fischer to hawthorn projections, What goes up and what goes down?
Right side is down | Left side is up
37
Anomers vis epimers
Anomers differ at the anomeric carbon | Epimers differ at locations other than the anomeric carbon