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Enzyme Regulation Flashcards

(105 cards)

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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
Zymogens have ___ ____ of one or more peptide bonds of the protein
specific cleavage
26
Three examples of zymogens:
1. Insulin 2. Proteolytic enzymes 3. Blood clotting factors
27
Insulin, proteolytic enzymes, and blood clotting factors are examples of ____
zymogens
28
Insulin is generated by ___ of a specific peptide from ____
removal, proinsulin
29
The activation of insulin is by the ___ of a specific peptide from the ___ ___ molecule.
removal, inactive proinsulin
30
Proteolytic enzymes of the ___ ___ are synthesized as zymogens in the pancreas and stomach
digestive tract
31
Blood clotting factors are produced by activation of zymogens of ___ ____ ___
blood clotting factors
32
____ are synthesized as zymogens in the pancreas and stomach
proteolytic
33
Activation of insulin by the ____ of a specific peptide from the ____ proinsulin molecule
removal, inactive
34
___ is a peptide hormone
insulin
35
Insulin is the active form of ___
proinsulin
36
Trypsin originates in the ___
pancreas
37
Chymotrypsin originates in the ___
pancreas
38
Carboxypeptidase originates in the __
pancreas
39
Elastase originates in the ___
pancreas
40
Pepsin originates in the ___
stomach !!
41
What is the active protein of trypsinogen?
trypsin
42
What is the active protein of chymotrypsinogen?
chymotrypsin
43
What is the active protein of procarboxypeptidase?
carboxypeptidase
44
What is the active protein of proelastase?
elastase
45
What is the active protein of pepsinogen?
pepsin
46
What is the zymogen of the active protein trypsin?
trypsinogen
47
What is the zymogen of the active protein chymotrypsin?
chymotrypsinogen
48
What is the zymogen of the active protein carboxypeptidase?
procarboxypeptidase
49
What is the zymogen of the active protein elastase?
proelastase
50
What is the zymogen of the active protein pepsin?
pepsinogen
51
In the proteolytic activation of chymotrypsinogen, peptide bonds are ___ at the ends
cut
52
Chymotrypsin attacks __ in the proteolytic activation process
itself
53
___ chymotrypsin is the fully active form
alpha
54
Chymotrypsin's proteins are connected by what type of bonds?
disulfide bonds
55
The zymogen activation steps lead to __ ___ ____
blood clot formation
56
What are the two blood clot formation pathways?
extrinsic/tissue factor intrinsic/contract activation
57
Fibrinogen is __ in blood
soluble
58
Fibrin is ___ in blood
insoluble
59
Fibrin forms __ __
blood clots
60
An active factor activates an ___ ___
inactive factor
61
___ activates blood clotting factors in the intrinsic pathway
proteases
62
___ are forms of an enzyme that differ in their quaternary structure, with different numbers of distinct polypeptide subunits.
Isozymes
63
Isozymes are forms of an ___ that differ in their ____ ___, with different numbers of distinct ____ ____.
enzyme, quaternary structure, polypeptide subunits
64
Lactase dehydrogenase is an example of what?
isozyme
65
There are __ different subunits of LDH
5
66
__ __ LDH is mainly A4 isozyme
skeletal muscle
67
A4 isozyme is ____
skeletal muscle
68
___ __ LDH is mainly B4 isozyme
heart muscle
69
B4 isozyme is ___
heart muscle
70
Skeletal muscle LDH produces___ __ in ___ conditions
lactic acid in anaerobic
71
Heart muscles LSD uses __ __ in ___ conditions
lactic acid in aerobic
72
The two isozymes of LDH work in __ directions
opposite
73
__ ___ are proteins that bind to enzymes and influence their activity
modulator proteins
74
Modulator proteins __ ___ and ___ the active site of enzymes
cover up and inhibit
75
cAMP-dependent protein kinase are examples of what?
modulator proteins
76
cAMP-dependent protein kinase are made up of __ and ___
catalytic subunits (C) regulatory subunits (R)
77
In cAMP-dependent protein kinase, catalytic subunits are ___ active
enzymatically
78
In cAMP-dependent protein kinase, regulatory subunits are ___ ___ that bind the to __ subunits and ___ their activity
modulatory proteins, C, inhibit
79
The modulator protein prevents the ___ from binding to the __ __ and being converted into a product module
substrate, active site
80
in cAMP dependent protein kinase, the R subunits __ C subunit activity
inhibit
81
cAMP dependent protein kinase is active when R subunits are ___
disconnected
82
___ ___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
allosteric regulation
83
allosteric regulation is the ___ or ___ of enzyme activity
inhibition or activation
84
allosteric regulation occurs through __ ___ ___ of small molecules to a site __ than the active site of the enzyme
non covalent binding, different
85
__ __ is when the final product F binds to enzyme 1 and inhibits enzyme 1(allosteric enzyme)
feedback inhibition
86
___ ___ shuts down the pathway and prevents further synthesis of final product F.
feedback inhibition
87
Final product F is non competitive inhibitor making it an ___ ___
allosteric enzyme
88
Feedback inhibition is what type of regulation?
Non competitive
89
What is the graph shape of allosteric enzymes?
sigmoid/S shaped curve s
90
What is the s shaped curve of allosteric enzymes caused by?
cooperative binding
91
"allo" means a ____ site
different
92
cooperative binding occurs because allosteric enzymes are composed of __ __
multiple subunits
93
Regulatory molecules (allosteric enzymes), including feedback inhibitors, bind to the enzymes and __ or __ their activity
inhibit or stimulate
94
Allosteric effectors change the ___ structure of the subunit polypeptides and/or change the ____ interactions
3D, subunit
94
Allosteric effectors change the 3D structure of the __ ___ and/or change the ___ interactions
subunit polypeptides, subunit
95
A sigmoid (s shaped curve) is produced by ___ ___ of substrate molecules to an ___ ___
cooperative binding, allosteric enzyme
96
For an allosteric enzyme, the more substrates there is more __ states are converted into __ states
T (taut), R (relaxed)
97
For allosteric enzymes, the __ state is inactive
T (taut)
98
For allosteric enzymes, the __ states is active
R (relaxed)
99
The existence of _ and _ states of an allosteric enzyme can account for __ __ of substrate molecules and the S-shaped curves
T and R, cooperative binding
100
Dimer is ...
Two subunits side by side
101
R state of an allosteric enzyme __ bind substrates
can
102
T state of an allosteric enzyme ___ bind substrates
cannot
103
T state an allosteric enzyme can convert to the __ state
R
104
When T state is converted to the R state, more ___ are open, producing more ___
substrates, products

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