Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MFoM > 02c: Enzyme Kinetics and Inhibition > Flashcards

02c: Enzyme Kinetics and Inhibition Flashcards

1
Q

In unimolecular irreversible reaction, rate of P formation equals (X) and is directly proportional to (Y).

A

X = rate of A disappearance

Y = [A]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

First order rate constant units.

A

1/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Second order reaction rate constant units.

A

1/Ms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In unimolecular reversible reaction: large Keq favors (reactants/products).

A

Products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What’s the plot shape of substrate concentration versus reaction velocity in typical enzyme-catalyzed reaction?

A

Hyperbolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Zero order reaction is found at what substrate concentration? The reaction velocity equals:

A

When [S] much greater (20x) Km

Vo = Vm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List Michaelis-Menten assumptions.

A
  1. ES forms
  2. No back reaction
  3. Initial v used
  4. [ES] in steady state
  5. Negligible substrate depletion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does a larger Km affect the plot/curve shape?

A

Flattens out curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Kd is known as (X) and tells you about (Y).

A 
X = dissociation constant
Y = binding affinity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Small Km is indicative of (strong/weak) binding.

A

Strong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Kcat is formally termed:

A

Turnover number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Catalytic efficiency of enzyme represented by:

A

Kcat/Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What defines a “perfect enzyme”?

A

Kcat/Km in range of

10(^8) - 10(^9)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Units for catalytic efficiency:

A

1/Ms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

It’s recommended to use (linear/nonlinear) regression of data to determine Km and Vm.

A

Nonlinear (hyperbolic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is it possible to linearize Michaelis-Menten?

A

Yes - take reciprocal of both sides to get Lineweaver-Burk plot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Lineweaver-Burk plot slope represents:

A

Km/Vm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lineweaver-Burk plot x-intercept represents:

A

-1/Km

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Lineweaver-Burk plot y-intercept represents:

A

1/Vm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Increasing Vm will have what effect on Lineweaver-Burk plot?

A

Bring y-intercept closer to origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Increasing Km will have what effect on Lineweaver-Burk plot?

A

Bring X-intercept closer to origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

A “perfect enzyme” will have what difference in Lineweaver-Burk plot compared to another enzyme?

A

Smaller slope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Can Kcat be determined from (michaelis-menten/lineweaver-Burke) plot? What’s the equation?

A

Either, as long as [E]t and Vmax are determined;

Vm = Kcat*[E]t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Bi-substrate reaction classes:

A
  1. Sequential

2. Ping-pong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
All substrates bind in specific order before any product released describes which bi-substrate reaction class?
Sequential (ordered)
26
All substrates bind randomly before any product released describes which bi-substrate reaction class?
Sequential (random)
27
One substrate binds and releases product before second substrate binds describes which bi-substrate reaction class?
Ping-pong (double-displacement)
28
(Competitive/uncompetitive/non competitive) inhibitors are irreversible.
None - all are reversible
29
Competitive inhibitors bind to:
Free enzyme only
30
T/F: competitive inhibitors don't affect the amount of ES complex formed.
False
31
How does Km change in presence of competitive inhibitor.
It doesn't! Only apparent value changes
32
How does apparent Km value change in presence of competitive inhibitor?
Increase
33
How does apparent Vm value change in presence of competitive inhibitor?
No change
34
How does apparent catalytic activity value change in presence of competitive inhibitor?
Decrease
35
Uncompetitive inhibitors bind to:
ES complex only (not at active site)
36
How does uncompetitive inhibitor hinder reaction?
Distorts active site, making it catalytically inactive
37
How does apparent Vm value change in presence of uncompetitive inhibitor?
Decreases
38
How does apparent Km value change in presence of uncompetitive inhibitor?
Decreases
39
How does apparent catalytic activity value change in presence of uncompetitive inhibitor?
No change
40
At low [S], which inhibitor(s) decrease rate?
Competitive and Noncompetitive
41
At low [S], which inhibitor(s) don't change rate?
Uncompetitive
42
Noncompetitive inhibitors bind to:
Free enzyme or ES complex
43
Do (X) inhibitors bind with greater Ki to free enzyme or ES complex?
X = non-competitive Bind with same Ki to either
44
How does noncompetitive inhibitor hinder reaction?
Distorts enzyme structure, preventing alignment of catalytic center
45
How does apparent Vm value change in presence of noncompetitive inhibitor?
Decreases
46
How does apparent Km value change in presence of noncompetitive inhibitor?
No change
47
How does apparent catalytic activity value change in presence of noncompetitive inhibitor?
Decreases
48
Enzymatic activity can be precisely regulated in which ways?
1. Allosteric control 2. Regulatory proteins 3. Reversible covalent modifications 4. Proteolytic activity
49
Allosteric enzymes do not obey (X) because the [S] v. Vo plot has which shape?
X = michaelis-menten kinetics Sigmoidal shape
50
Sigmoidal curves result from (X) cooperativity, indicating which change in Km?
X = positive Decrease Km with increase in [S]
51
In allosteric control, (X) effector is same as substrate and (Y) effector is different from substrate.
``` X = homotropic Y = heterotropic ```
52
Does allosteric control change Km or Vm?
Can change either or both
53
Are allosteric enzymes monomeric or oligomeric?
Can be either
54
ATCase is an enzyme that catalyzes:
first step in pyrimidine biosynthesis pathway
55
(X) is a negative effector of the ATCase enzyme.
X = CTP
56
Describe structure of ATCase.
6 catalytic subunits (trimers) and 6 regulatory subunits (dimers)
57
ATCase is in equilibrium between which two states? Which is favored?
Tense and relaxed; Tense favored (200:1)
58
(X), the ATCase substrate, stabilizes which of the two enzyme states?
X = aspartate Relaxed state
59
The final product of ATCase pathway, (X), stabilizes which of the two enzyme states?
X = CTP Tense state
60
Name a positive effector of ATCase.
ATP
61
The positive/negative effectors of ATCase bind which subunits on enzyme?
Regulatory
62
Give example of reversible, covalent modifications of enzymes.
Phosphorylation and de-phosphorylation
63
T/F: Phosphorylation always increases enzyme activity.
False
64
Kinases (add/remove) (X) groups to/from proteins using:
Add X = phosphate ATP
65
Phosphatases (add/remove) (X) groups to/from proteins using:
Remove X = phosphate H2O (hydrolysis)

MFoM (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions