Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Lecture 3: Structure/Function Relationships of Proteins: Myoglobin & Hemoglobin > Flashcards

Lecture 3: Structure/Function Relationships of Proteins: Myoglobin & Hemoglobin Flashcards

1
Q

What is a molecule that binds?

A

ligand

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

What is the small region where the ligand binds?

A

binding site

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

What forces are used during non-covalent binding?

A

non-covalent forces

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

What is K?

A

Equilibrium Constant

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

What is k?

A

Rate constant

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

What is another name for the ligand-binding site?

A

Catalytic (Active) site

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

Are the Kd and Ka inverse?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True or False; Better drugs have a larger kd

A

False; Better drugs have a smaller kd (disassociation constant) which means they have a higher association constant and high affinity.

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

Which will have the highest affinity?

ka= 10^5
ka= 10^-5
A

ka= 10^5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are (3) notes to remember about binding? (Exam review)

A

1) Binding occurred at Eq
2) Binding is reversible
3) Total [L]= Pre[L] because protein is saturated with ligand

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

What is kd in reference to [L]?

A

[L] at which 1/2 protein bound to ligand

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

What can we assume at y-max as it relates to protein availability?

A

All of protein is bound to ligand

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

What is the Langmuir Isotherm Equation

A

[PL]= [P]total [L] total/ Kd + [L] Total

*Shows difference bt amounts of protein/ligand

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

What are suicide inhibitors?

A

They induce a lot of side effects and are very reactive

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

Which model only allow certain ligands to bind?

A

Lock & Key Model

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

What are (3) ways Lock & Key Model complement?

A

size shape charge hydrophobic/hydrophilic character

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

Which model occurs upon ligand binding and causes a conformational change

A

Induced Fit Model

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

True or False: Induced Fit allows for loose binding of the ligand

A

False; Induced Fit allows for tight binding of the ligand.

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

True or False: Induced fit can increase the affinity of the protein for a second ligand

A

True

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

True or False; only the ligand can change their conformations in Induced Fit

A

False; Both the ligand and protein can change their conformations

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

What is a goal of Myoglobin?

A

need to store O2 for metabolism but protein side chains lack an affinity for O2

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

How does Myoglobin store O2?

A

Capture molecule with Heme moiety,

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

True or False; Myoglobin is the main O2 storage in bacteria

A

False; Main O2 storage in Mammals.

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

True or False; Increase in Delta G means an unfavorable and increase in kd

A

True; increase in kd means decrease in affinity and unfavorable reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

True or False; Transition metals that bind to Myoglobin cause free radicals

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

True or False; O2 binds to myoglobin irreversibly

A

False; binds to myoglobin reversibly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How many subunits does Heme contain?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the subunits that Heme contain

A

Alpha2-Beta2

29
Q

True or False; Heme is a weak chromophore

A

False; it is a strong chromophore

30
Q

What is the prosthetic Group of Hemoglobin

A

Heme

31
Q

What are the 2 interchangable structural states of Hemoglobin

A

T/R

32
Q

What do we know about T structural states?

A

Most stable when NOT bound to O2

33
Q

What do we know about R structural states?

A

O2 binding promotes transitioning

34
Q

True or False; O2 binding is allosteric and cooperative

A

True

35
Q

True or False; Hemoglobin has a few binding sites

A

False; Hb has multiple binding sites

36
Q

What is it called when binding sites are able to interact with each other?

A

Cooperatively

37
Q

What is bound to iron in Heme?

A

4- Pyrole Rings
Proximal His
O2

38
Q

What does R in R-state stand for?

A

Relaxed State

39
Q

What does T in T-State stand for?

A

Tense state

40
Q

T transforms to R when what happens

A

O2 binds to T causing a conformational change

41
Q

Which state has a high affinity for O2>

A

R-state

42
Q

True or false: Blood in lungs has a higher pH than blood in tissues

A

True; The blood is most acids in the tissues

43
Q

True or false; O2 has a higher affinity for a lower pH

A

False; O2 has a higher affinity for a higher pH

44
Q

When is O2 released? at higher or lower pH?

A

Lower pH

45
Q

What is the Bohr Effect

A

the pH difference between the lungs and metabolic tissues increasing the O2 transfer efficiency

46
Q

Explain how Hb picks up and distributes O2?

A

Hb pick up O2 from Lungs (high affinity/high pH) and distributes it to the tissues of the body (low affinity/low pH)

47
Q

True or False; When protonated, His favors the T-state

A

True (lower pH)

pronated (acidic)

48
Q

True or False; When deprotonated, His favors the T-state

A

False; depronation= His favors R-state

depronated (higher pH)

49
Q

What AA contributes to the Bohr Effect

A

Histidine

50
Q

How is CO2 exported via Hemoglobin?

A

1) Dissolved bicarbonate in the blood

2) In the form of a carbamate on the Amino Terminal Residue of each Hb polypeptide subunit

51
Q

True or False; When Hb binds to O2 in the lungs, CO2 is released

A

True

52
Q

BPG is found where?

A

RBC;

53
Q

Where does BPG bind to O2?

A

Between the Beta subunits

54
Q

True or False; BPG stabilizes the R-State

A

False; it stabilizes the T-state

55
Q

True or False; purified HB has a lot of BPG in the blood>

A

True

56
Q

How can you force a drug to bind to a protein if it has a very high Kd?

A

Increase amount of ligand present; downside will give you lots of side effects

57
Q

What does Kd depend on?

A

pH

specificity between the protein and ligand

58
Q

What are (3) assumptions about Langmur Equation?

A

1) Binding is at eq
2) Binding is reversible
3) Total [L] > Total [P] meaning protein is saturated with ligand. So most of the ligand is NOT bound to the protein.

59
Q

True or False; Fractional occupancy of the protein receptor increases as the binding affinity increases

A

True

60
Q

True or False; Heme group has a porphyrin ring with a Fe atom

A

True

61
Q

Is Hb tetrameric or monomeric?

A

tetrameric

62
Q

Is Mb tetrameric or monomeric?

A

Monomeric

63
Q

How many O2 can Hb bind to?

A

4-O2

64
Q

How may O2 can Mb bind to?

A

1-O2

65
Q

How many peptide chains does Mb consist of?

A

single

66
Q

Where is Mb found

A

tissues

67
Q

What is bound to iron in Heme?

A

4-Pyrole rings, Distal histidine, O2

68
Q

Wha type of binding does Hb bind?

A

Cooperative Binding

69
Q

What type of bonds does 2,3-BPG form with the R-state?

A

None. It only binds to the T-state/stabilizes it. (via ion interactions)

Biochemistry (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions