Enzyme Regulation Flashcards

1
Q

Enzyme ___ is the ability of an enzyme to catalyze only one particular reaction

A

specificity

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2
Q

Specificity is due to the ____ ____ of enzyme and substrate

A

structural complementarity

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3
Q

The substrate glucose is bound to the active site of what enzyme?

A

hexokinase

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4
Q

What hypothesis considers that the enzyme’s active site is modified/flexible upon binding of the substrate?

A

induced fit

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5
Q

What hypothesis considers that the enzyme as the lock and the substrate fits in as the key?

A

lock and key

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6
Q

What are the four mechanisms of enzyme regulation?

A

genetic control, covalent modification, specialized controls , allosteric regulation

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7
Q

___ controls the amount of enzyme (gene induction of repression)

A

Genetic

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8
Q

____ ____ is the attachment of chemical groups such as phosphate groups

A

Covalent modification

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9
Q

Zymogens, isozymes, and modular proteins are examples of what?

A

Specialized controls

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10
Q

__ ___ is an inhibitor or activator binds to the enzyme at a site different than the active site.

A

Allosteric regulation

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11
Q

The phosphate groups are attached through the ___ side chains of amino acids, such as serine.

A

-OH

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12
Q

What donates the phosphate molecule in the attachment of a phosphate group via covalent modification?

A

ATP

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13
Q

The reversible covalent attachment of phosphate groups ____ enzyme actitivy

A

regulates

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14
Q

Protein ___ is an enzyme that adds a phosphate group to an enzyme

A

kinase

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15
Q

Protein __ is an enzyme that removes a phosphate group from an enzyme

A

phosphatase

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16
Q

Enzyme is catalytically inactive when the phosphate is ___

A

attached

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17
Q

Enzyme is catalytically active when the phosphate is ___

A

removed

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18
Q

The phosphate group addition affects protein __

A

folding

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19
Q

The __ ___ ___ is removed from the enzyme when adding a phosphate group

A

amino acid sidechain

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20
Q

Phosphate ___ the active site of an enzyme, making it inactive

A

closes

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21
Q

Attachment of phosphate groups can be ___

A

reversed

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22
Q

Zymogens are _____

A

proenzymes

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23
Q

___ are inactive precursors of enzymes or other proteins that acquire full activity by specific cleavage of one or more peptide bonds of the protein

A

Zymogens

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24
Q

Zymogens are ___ precursors of enzymes

A

inactive

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25
Q

Zymogens have ___ ____ of one or more peptide bonds of the protein

A

specific cleavage

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26
Q

Three examples of zymogens:

A
  1. Insulin
  2. Proteolytic enzymes
  3. Blood clotting factors
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27
Q

Insulin, proteolytic enzymes, and blood clotting factors are examples of ____

A

zymogens

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28
Q

Insulin is generated by ___ of a specific peptide from ____

A

removal, proinsulin

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29
Q

The activation of insulin is by the ___ of a specific peptide from the ___ ___ molecule.

A

removal, inactive proinsulin

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30
Q

Proteolytic enzymes of the ___ ___ are synthesized as zymogens in the pancreas and stomach

A

digestive tract

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31
Q

Blood clotting factors are produced by activation of zymogens of ___ ____ ___

A

blood clotting factors

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32
Q

____ are synthesized as zymogens in the pancreas and stomach

A

proteolytic

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33
Q

Activation of insulin by the ____ of a specific peptide from the ____ proinsulin molecule

A

removal, inactive

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34
Q

___ is a peptide hormone

A

insulin

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35
Q

Insulin is the active form of ___

A

proinsulin

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36
Q

Trypsin originates in the ___

A

pancreas

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37
Q

Chymotrypsin originates in the ___

A

pancreas

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38
Q

Carboxypeptidase originates in the __

A

pancreas

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39
Q

Elastase originates in the ___

A

pancreas

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40
Q

Pepsin originates in the ___

A

stomach !!

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41
Q

What is the active protein of trypsinogen?

A

trypsin

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42
Q

What is the active protein of chymotrypsinogen?

A

chymotrypsin

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43
Q

What is the active protein of procarboxypeptidase?

A

carboxypeptidase

44
Q

What is the active protein of proelastase?

A

elastase

45
Q

What is the active protein of pepsinogen?

A

pepsin

46
Q

What is the zymogen of the active protein trypsin?

A

trypsinogen

47
Q

What is the zymogen of the active protein chymotrypsin?

A

chymotrypsinogen

48
Q

What is the zymogen of the active protein carboxypeptidase?

A

procarboxypeptidase

49
Q

What is the zymogen of the active protein elastase?

A

proelastase

50
Q

What is the zymogen of the active protein pepsin?

A

pepsinogen

51
Q

In the proteolytic activation of chymotrypsinogen, peptide bonds are ___ at the ends

A

cut

52
Q

Chymotrypsin attacks __ in the proteolytic activation process

A

itself

53
Q

___ chymotrypsin is the fully active form

A

alpha

54
Q

Chymotrypsin’s proteins are connected by what type of bonds?

A

disulfide bonds

55
Q

The zymogen activation steps lead to __ ___ ____

A

blood clot formation

56
Q

What are the two blood clot formation pathways?

A

extrinsic/tissue factor
intrinsic/contract activation

57
Q

Fibrinogen is __ in blood

A

soluble

58
Q

Fibrin is ___ in blood

A

insoluble

59
Q

Fibrin forms __ __

A

blood clots

60
Q

An active factor activates an ___ ___

A

inactive factor

61
Q

___ activates blood clotting factors in the intrinsic pathway

A

proteases

62
Q

___ are forms of an enzyme that differ in their quaternary structure, with different numbers of distinct polypeptide subunits.

A

Isozymes

63
Q

Isozymes are forms of an ___ that differ in their ____ ___, with different numbers of distinct ____ ____.

A

enzyme, quaternary structure, polypeptide subunits

64
Q

Lactase dehydrogenase is an example of what?

A

isozyme

65
Q

There are __ different subunits of LDH

A

5

66
Q

__ __ LDH is mainly A4 isozyme

A

skeletal muscle

67
Q

A4 isozyme is ____

A

skeletal muscle

68
Q

___ __ LDH is mainly B4 isozyme

A

heart muscle

69
Q

B4 isozyme is ___

A

heart muscle

70
Q

Skeletal muscle LDH produces___ __ in ___ conditions

A

lactic acid in anaerobic

71
Q

Heart muscles LSD uses __ __ in ___ conditions

A

lactic acid in aerobic

72
Q

The two isozymes of LDH work in __ directions

A

opposite

73
Q

__ ___ are proteins that bind to enzymes and influence their activity

A

modulator proteins

74
Q

Modulator proteins __ ___ and ___ the active site of enzymes

A

cover up and inhibit

75
Q

cAMP-dependent protein kinase are examples of what?

A

modulator proteins

76
Q

cAMP-dependent protein kinase are made up of __ and ___

A

catalytic subunits (C)
regulatory subunits (R)

77
Q

In cAMP-dependent protein kinase, catalytic subunits are ___ active

A

enzymatically

78
Q

In cAMP-dependent protein kinase, regulatory subunits are ___ ___ that bind the to __ subunits and ___ their activity

A

modulatory proteins, C, inhibit

79
Q

The modulator protein prevents the ___ from binding to the __ __ and being converted into a product module

A

substrate, active site

80
Q

in cAMP dependent protein kinase, the R subunits __ C subunit activity

A

inhibit

81
Q

cAMP dependent protein kinase is active when R subunits are ___

A

disconnected

82
Q

___ ___is the inhibition or activation of enzyme activity through non covalent binding of small molecules to a site different than the active site of the enzyme

A

allosteric regulation

83
Q

allosteric regulation is the ___ or ___ of enzyme activity

A

inhibition or activation

84
Q

allosteric regulation occurs through __ ___ ___ of small molecules to a site __ than the active site of the enzyme

A

non covalent binding, different

85
Q

__ __ is when the final product F binds to enzyme 1 and inhibits enzyme 1(allosteric enzyme)

A

feedback inhibition

86
Q

___ ___ shuts down the pathway and prevents further synthesis of final product F.

A

feedback inhibition

87
Q

Final product F is non competitive inhibitor making it an ___ ___

A

allosteric enzyme

88
Q

Feedback inhibition is what type of regulation?

A

Non competitive

89
Q

What is the graph shape of allosteric enzymes?

A

sigmoid/S shaped curve s

90
Q

What is the s shaped curve of allosteric enzymes caused by?

A

cooperative binding

91
Q

“allo” means a ____ site

A

different

92
Q

cooperative binding occurs because allosteric enzymes are composed of __ __

A

multiple subunits

93
Q

Regulatory molecules (allosteric enzymes), including feedback inhibitors, bind to the enzymes and __ or __ their activity

A

inhibit or stimulate

94
Q

Allosteric effectors change the ___ structure of the subunit polypeptides and/or change the ____ interactions

A

3D, subunit

94
Q

Allosteric effectors change the 3D structure of the __ ___ and/or change the ___ interactions

A

subunit polypeptides, subunit

95
Q

A sigmoid (s shaped curve) is produced by ___ ___ of substrate molecules to an ___ ___

A

cooperative binding, allosteric enzyme

96
Q

For an allosteric enzyme, the more substrates there is more __ states are converted into __ states

A

T (taut), R (relaxed)

97
Q

For allosteric enzymes, the __ state is inactive

A

T (taut)

98
Q

For allosteric enzymes, the __ states is active

A

R (relaxed)

99
Q

The existence of _ and _ states of an allosteric enzyme can account for __ __ of substrate molecules and the S-shaped curves

A

T and R, cooperative binding

100
Q

Dimer is …

A

Two subunits side by side

101
Q

R state of an allosteric enzyme __ bind substrates

A

can

102
Q

T state of an allosteric enzyme ___ bind substrates

A

cannot

103
Q

T state an allosteric enzyme can convert to the __ state

A

R

104
Q

When T state is converted to the R state, more ___ are open, producing more ___

A

substrates, products