Study sets matching "enzyme regulation"

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Study sets matching "enzyme regulation"

26 terms
Enzyme Regulation
What mechanism is the major covalent m…
Why is it necessary to regulate enzyme…
What is a competitive inhibitor?
How can competitive inhibtion be rever…
Phosphorylation/dephosphorylation
-Enzymes are capable of rapid metabolism... -Physicological cond…
Inhibtory modulator that competes with the substrate to bind…
Increase [S] to outcompete the lower Km enzyme for the inhibi…
What mechanism is the major covalent m…
Phosphorylation/dephosphorylation
Why is it necessary to regulate enzyme…
-Enzymes are capable of rapid metabolism... -Physicological cond…
Enzyme Regulation
what does competitive inhibitors do
what happens when the active site for…
what is penicillin
what do noncompetitive inhibitors do
1. mimic the substrate and bind with the enzyme... 2. the active…
it poisons the enzyme
penicillin is a competitive inhibitor of enzymes in the bacte…
1. bond at the back of the enzyme (allosteric site) and cause…
what does competitive inhibitors do
1. mimic the substrate and bind with the enzyme... 2. the active…
what happens when the active site for…
it poisons the enzyme
16 terms
Enzyme Regulation
Substrate/Cofactor availability
Product Accumulation
Genetic regulation
Allosteric Regulation
Availability of substrates and cofactors typically determines…
As product accumulates, apparent rate of enzymatic reaction w…
Genetic regulation of enzyme synthesis and decay determines t…
when enzymatic activity is activated/inhibited through noncov…
Substrate/Cofactor availability
Availability of substrates and cofactors typically determines…
Product Accumulation
As product accumulates, apparent rate of enzymatic reaction w…
49 terms
Enzyme Regulation
enzymes lower ________
enzymes
in vivo
conformation of the substrate and rece…
activation energy
...
living
fit each other
enzymes lower ________
activation energy
enzymes
...
9 terms
Enzyme Regulation
3 ways to regulate enzymes
Ammount of enzyme changed by
Allosteric enzymes
Allosteric regulation
1. Change # of present enzymes... 2. change activity of enzyme b…
1. modifying gene expression... 2. activation/deactivation of ex…
2 conformations with different binding affinities
at REGULATORY, NOT CATALYTIC site; produced by activators/inh…
3 ways to regulate enzymes
1. Change # of present enzymes... 2. change activity of enzyme b…
Ammount of enzyme changed by
1. modifying gene expression... 2. activation/deactivation of ex…
Enzyme Regulation
Indicators of tissue damage by measuri…
Zymogen
Blood Coagulation Cascade
Thrombin
If intracellular enzymes become higher in the blood, this may…
Inactive form of a protein; a precursor. Proteolytic cleavage…
Involves zymogen activation of serine proteases in the presen…
Water-soluble, synthesized on the membrane surface. ... -N termi…
Indicators of tissue damage by measuri…
If intracellular enzymes become higher in the blood, this may…
Zymogen
Inactive form of a protein; a precursor. Proteolytic cleavage…
67 terms
Enzyme Regulation
Feedback-inhibited Enzymes
Covalently modified Enzymes
Allosteric Enzymes
Zymogens and Proenzymes
Excessive build up of an end product in a pathway inhibits to…
Reversible attachment of small molecules alter their activity…
Incur conformational changes via reversible, non-covalent bin…
Become activated by proteolytic cleavage of inactive precurso…
Feedback-inhibited Enzymes
Excessive build up of an end product in a pathway inhibits to…
Covalently modified Enzymes
Reversible attachment of small molecules alter their activity…
17 terms
Enzyme Regulation
Zymogen (proenzyme)
Enzymes are regulated by 4 primary means
Allosteric Interactions
Negative Feedback (Feedback Inhibition)
The inactive form of an enzyme (the way many enzymes are rele…
1. Proteolytic Cleavage (irreversible covalent modification)…
One form of enzyme regulation; it is the modification of an e…
Also called negative feedback; one of the products downstream…
Zymogen (proenzyme)
The inactive form of an enzyme (the way many enzymes are rele…
Enzymes are regulated by 4 primary means
1. Proteolytic Cleavage (irreversible covalent modification)…
15 terms
Enzyme Regulation
How to increase/ decrease activity
Metabolite flow is uni or multidirecti…
Compartmentation of enzymes
Second messengers
Increase or decrease [E total] respectively, since, ... Vmax= k…
unidirectional, concentration gradient
Conflicting metabolic pathways are restricted to specific com…
Many hormones produce them, allosteric effectors (both positi…
How to increase/ decrease activity
Increase or decrease [E total] respectively, since, ... Vmax= k…
Metabolite flow is uni or multidirecti…
unidirectional, concentration gradient
79 terms
Enzyme Regulation
Specificity
Structural complementarity
Weak forces
Lock and Key
The ability of an enzyme to catalyze only one particular reac…
Specificity is due to the ______ _______ of enzyme and substr…
Substrate binds to an enzyme through _____ _____, such as H b…
One type of enzyme fits one type of molecule. Change its shap…
Specificity
The ability of an enzyme to catalyze only one particular reac…
Structural complementarity
Specificity is due to the ______ _______ of enzyme and substr…
35 terms
Enzyme Regulation
3 strategies to regulate enzymes
Define mass action and explain its sig…
What are the 3 types of inhibition
What are allosteric enzymes?
1. changing the amount of the enzyme itself... 2. changing the a…
-definition: the change in the concentration of the initial r…
1. Competitive inhibition: comes from the product of the enzy…
-have 2+ conformations that change in affinity for binding th…
3 strategies to regulate enzymes
1. changing the amount of the enzyme itself... 2. changing the a…
Define mass action and explain its sig…
-definition: the change in the concentration of the initial r…
45 terms
Enzyme Regulation
lineweaver-burk plot
drawbacks of lineweaver burk plot
inhibitor
reversible competitive inhbitors
vo = vmax[s]/(km+s)
must reach vmax at high [S] to determine vmax... vo = -km(vo/s)…
a molecule that reduce efficiency of an enzyme.... -affects kcat…
binds at active site to compete with substrate.
lineweaver-burk plot
vo = vmax[s]/(km+s)
drawbacks of lineweaver burk plot
must reach vmax at high [S] to determine vmax... vo = -km(vo/s)…
18 terms
Enzyme Regulation
Rate Limiting Step
3 ways enzyme activity is regulated
Compartmentalization: Separation in Sp…
Compartmentalization: Separation in Time
- the slowest step in a pathway... - target of regulation and in…
1. comparmentalization... 2. substrate availability... 3. enzyme qu…
- prevents a futile cycle... e.g.: 1. FA synthesis: cystol, FA o…
- prevents futile cycles... e.g.: gylcolysis and gluconeogenesis…
Rate Limiting Step
- the slowest step in a pathway... - target of regulation and in…
3 ways enzyme activity is regulated
1. comparmentalization... 2. substrate availability... 3. enzyme qu…
34 terms
Enzyme Regulation
Why enzyme regulation matters
Five major mechanisms by which enzymes…
Allosteric control
Cooperativity
So that enzymes only function at times of need
1. Allosteric control... 2. Reversible covalent modification... 3.…
-Allosteric enzymes contain sites other than the active site…
-Most allosteric enzymes such as ATCase exhibit cooperativity…
Why enzyme regulation matters
So that enzymes only function at times of need
Five major mechanisms by which enzymes…
1. Allosteric control... 2. Reversible covalent modification... 3.…
7 terms
Enzyme Regulation
Competitive Inhibition
Noncompetitive Inhibition
Positive Allosteric Inhibition
Negative Allosteric Inhibition
inhibitor and substrate both capable of binding to active sit…
substrate binds to active site and inhibitor binds to alloste…
lack of activator=low affinity between enzyme and substrate... a…
inhibitor binds=low affinity between enzyme and substrate... sub…
Competitive Inhibition
inhibitor and substrate both capable of binding to active sit…
Noncompetitive Inhibition
substrate binds to active site and inhibitor binds to alloste…
enzyme regulation
regulatory enzyme
allosteric enzyme
feedback inhibition
protein kinases
An enzyme having a regulatory function through its capacity t…
A regulatory enzyme, with catalytic activity modulated by the…
Inhibition of an allosteric enzyme at the beginning of a meta…
Enzymes that transfer the terminal phosphoryl group of ATP or…
regulatory enzyme
An enzyme having a regulatory function through its capacity t…
allosteric enzyme
A regulatory enzyme, with catalytic activity modulated by the…
7 terms
Enzyme regulation
Glucokinase/Hexokinase
Phosphofructokinase-1
Pyruvate kinase
Pyruvate dehydrogenase complex
Inhibited: Glucose-6-phosphate
Inhibited: Citrate/ATP... Activated: AMP/ADP/Fructose-2,6-bispho…
Inhibited: Acetyl-CoA/ATP... Activated: Fructose-1,6-bisphosphog…
Inhibited(allosteric): ATP/NADH/Acetyl-CoA... Activated(alloster…
Glucokinase/Hexokinase
Inhibited: Glucose-6-phosphate
Phosphofructokinase-1
Inhibited: Citrate/ATP... Activated: AMP/ADP/Fructose-2,6-bispho…
15 terms
Enzyme Regulation
Hexokinase
PFK-1
FBPase
Pyruvate Carboxylase
G6P Inhibit
ATP allosteric Inhibit, F26BP allosteric enhance
F26BP allosteric inhibit
AcCoA allosteric enhance
Hexokinase
G6P Inhibit
PFK-1
ATP allosteric Inhibit, F26BP allosteric enhance
7 terms
Enzyme Regulation
Feedback Control
Allosteric Control
Reversible Uncompetitive Inhibition
Reversible Competitive Inhibition
Regulation of an enzyme's activity by the product of a reacti…
Binding of a molecule at one site on a protein effects the bi…
Inhibitor does not compete with the substrate for the active…
Inhibitor competes with the substrate for binding to the acti…
Feedback Control
Regulation of an enzyme's activity by the product of a reacti…
Allosteric Control
Binding of a molecule at one site on a protein effects the bi…
22 terms
enzyme regulation
cofactors
coenzymes
fact
compartmentalized
non protein "helper" molecule that is either loosely or tight…
cofactors that are organic molecules... ex: vitamin c in buildin…
same coenzymes can be used by multiple enzymes and enzymes wi…
in eukaryotic cells, enzymes aren't floating around in the cy…
cofactors
non protein "helper" molecule that is either loosely or tight…
coenzymes
cofactors that are organic molecules... ex: vitamin c in buildin…
Enzyme Regulation
Enzyme Kinetics: [Enzyme]
Enzyme Kinetics: [Substrate]
Vmax
Km
-The rate of a reaction is dependent on [enzyme].... -Each enzym…
-The rate of a reaction is dependent on [substrate].... -For a g…
the maximum rate of reaction for a given [enzyme]
-the [substrate] at which the rate of reaction is half of Vma…
Enzyme Kinetics: [Enzyme]
-The rate of a reaction is dependent on [enzyme].... -Each enzym…
Enzyme Kinetics: [Substrate]
-The rate of a reaction is dependent on [substrate].... -For a g…
32 terms
Enzyme Regulation
hexokinase activators
hexokinase inhibitors
PFK activators
PFK inhibitors
glucose, Pi
G6P
Pi, AMP, NH3, F6P, F2,6,BP
citrate, ATP, H+, PEP
hexokinase activators
glucose, Pi
hexokinase inhibitors
G6P
Enzyme Regulation
Mechanism of Enzyme Regulation
Substrate concentration
Amount of enzyme
Allosteric control
Substrate Concentration, Amount of Enzyme, Allosteric Control…
has limitations, if no substrate enzyme isnt active, once abo…
Pro: changes rxn rate con: slow, gene activation, protein deg…
a molecule that binds to a site that isnt active site on enzy…
Mechanism of Enzyme Regulation
Substrate Concentration, Amount of Enzyme, Allosteric Control…
Substrate concentration
has limitations, if no substrate enzyme isnt active, once abo…
enzyme regulation
almost all biological reactions are ca…
6 ways to regulate enzyme activity
lactate dehydrogenase isozymes
biological role for lactate dehydrogen…
could proceed on their own... -this is due to regulation
-isozymes... -enzyme concentration... -covalent modification... -coope…
H and M subunits have different catalytic properties and can…
regenerate NAD+ through ox-phos after the CAC
almost all biological reactions are ca…
could proceed on their own... -this is due to regulation
6 ways to regulate enzyme activity
-isozymes... -enzyme concentration... -covalent modification... -coope…
enzyme regulation
allosteric site
positive allosteric regulator
negative allosteric site
feedback regulation
a location on the surface of an enzyme that is located some d…
when a molecule binds to an allosteric site and increases the…
a molecule that decreases the enzyme activity when it binds t…
the idea that when a pathway has generated a sufficient amoun…
allosteric site
a location on the surface of an enzyme that is located some d…
positive allosteric regulator
when a molecule binds to an allosteric site and increases the…
10 terms
enzyme regulation
regulatory enzymes
types of regulatory enzymes
allosteric regulation
what do most allosteric modulators alter
exhibit decreased/increase act in response to certain signals
allosteric regulation and reversible covalent modification
enzymes act is regulated thru reversible, noncovalent binding…
Km of enzyme but not max velocity of rxn
regulatory enzymes
exhibit decreased/increase act in response to certain signals
types of regulatory enzymes
allosteric regulation and reversible covalent modification
40 terms
Enzyme Regulation
Enzymes
Inheritable genetic diseases
Blood and enzymes
Enzymes are
Reaction catalyst of biological systems... highly specialized pr…
deficiency or total absence of enzyme or excess activity
can measure activity of enzyme in blood ... used as tissue diagn…
proteins
Enzymes
Reaction catalyst of biological systems... highly specialized pr…
Inheritable genetic diseases
deficiency or total absence of enzyme or excess activity
22 terms
Enzyme Regulation
allosteric site
allosteric effector
allosteric enzyme
postitive cooperation
a regulatory site on an enzyme that is separate from the cata…
binds to an allosteric site and regulates the enzymes activity
usually has more than one interacting subunit and 2 distinct…
when the binding of a substrate to one subunit facilitates th…
allosteric site
a regulatory site on an enzyme that is separate from the cata…
allosteric effector
binds to an allosteric site and regulates the enzymes activity
enzyme regulation
a regulatory site on an enzyme separat…
what binds to an allosteric site of an…
an allosteric enzyme has more than one…
allosteric sites are good ___ targets
allosteric site
allosteric effector
2
drug
a regulatory site on an enzyme separat…
allosteric site
what binds to an allosteric site of an…
allosteric effector
12 terms
Enzyme Regulation
activation
inhibition
feedback and allosteric control
inhibition
any process that starts or increases the action of an enzyme
any process that slows or stops the action of an enzyme
enzyme activity is regulated by the product of a reaction lat…
enzymes lose activity because of interaction with another mol…
activation
any process that starts or increases the action of an enzyme
inhibition
any process that slows or stops the action of an enzyme
Enzyme Regulation
Synthesis/ Degrade
Denature/ Renature
Binding Factors
Feedback Inhibition
most inefficient way to regulate, make an enzyme then destroy…
change the shape of and enzyme with pH, temperature, or ionic…
co-factors: elements... co-enzymes: vitamines
chemical pathway
Synthesis/ Degrade
most inefficient way to regulate, make an enzyme then destroy…
Denature/ Renature
change the shape of and enzyme with pH, temperature, or ionic…
Enzyme Regulation
Feedback Inhibition:
Committed Step:
Rate Limiting Step
Changing the activity of enzyme
when the product of a pathway inhibits a prior step in the pa…
the first step in the pathway that is unique to the pathway (…
the enzyme that catalyzes the slowest step in a pathway. ... - m…
1. Allosteric Modulation ... 2. Control Proteins ... 3. reversible…
Feedback Inhibition:
when the product of a pathway inhibits a prior step in the pa…
Committed Step:
the first step in the pathway that is unique to the pathway (…
Enzyme Regulation
Anabolic state
Catabolic state
Gluconeogensis
Glycolysis
State in which "materials" are in place to be utilized to bui…
State in which larger structures throughout the body are bein…
The production of glucose... Essential metabolic function in ca…
The breakdown of glucose for energy production
Anabolic state
State in which "materials" are in place to be utilized to bui…
Catabolic state
State in which larger structures throughout the body are bein…
33 terms
Enzyme Regulation
PFK-1
Gluconeogenesis
Pyruvate Kinase
Liver Pyruvate Kinase
Inhibited by ATP, Citrate. ... Activated by ADP, AMP, F26BP.
Inhibited by AMP, F26BP
Inhibited by ATP, alanine, acetyl CoA, fatty acids... Activated…
Inhibited by glucagon ---> PKA phosphorylates pyruvate kinase…
PFK-1
Inhibited by ATP, Citrate. ... Activated by ADP, AMP, F26BP.
Gluconeogenesis
Inhibited by AMP, F26BP
8 terms
Enzyme Regulation
Allosteric enzymes
Competitive inhibition
Noncompetetive inhibition
Uncompetitive/anti-competitive inhibit…
have both an active site for substrate binding and an alloste…
substance that mimics the substrate inhibits the enzyme by bi…
substance inhibits enzyme by binding elsewhere than active si…
enzyme inhibitor binds only to the formed E-S complex, preven…
Allosteric enzymes
have both an active site for substrate binding and an alloste…
Competitive inhibition
substance that mimics the substrate inhibits the enzyme by bi…
9 terms
Enzyme Regulation
Three reversible types
Competitive
Competitive Inhibition graph
Uncompetitive
Competitive ... Uncompetitive ... Mixed (noncompetitive is one).
The inhibitor reversibly competes for the active site. ... Effe…
Intercepts at the y axis (Vmax doesn't change). ... Km gets lar…
Inhibitor instead of competing with the substrate, binds to t…
Three reversible types
Competitive ... Uncompetitive ... Mixed (noncompetitive is one).
Competitive
The inhibitor reversibly competes for the active site. ... Effe…
11 terms
enzyme regulation
inhibitor
activator
allosteric site
allosteric regulation
a molecule that binds to the allosteric or active site of an…
a molecule that binds to the allosteric site of an enzyme and…
the site on an enzyme that is not the active site, where othe…
the regulation of enzyme activity by means of activators and…
inhibitor
a molecule that binds to the allosteric or active site of an…
activator
a molecule that binds to the allosteric site of an enzyme and…
Enzyme Regulation
What is the rate of reaction dependent…
what happens as more enzyme is added?
What affect does pH and temp have on t…
What happens when more substrate is ad…
the concentration of the enzyme and substrate
the rate of the reaction increases
the effective [enzyme] decreases (more enzyme is inactive or…
the rate of reaction increases until all enzymes are saturate…
What is the rate of reaction dependent…
the concentration of the enzyme and substrate
what happens as more enzyme is added?
the rate of the reaction increases
Enzyme Regulation
Substrate concentration is regulating…
High Km enzymes are a lot more depende…
Regulate amount of enzyme
Degrade the enzyme down to its amino a…
if you dont have high enough concentration, no reaction
IF you need to elevate it, has various limitations
have to increase the expression of its gene.. takes a lot of…
Fast process, but if you need enzyme again you have to remake…
Substrate concentration is regulating…
if you dont have high enough concentration, no reaction
High Km enzymes are a lot more depende…
IF you need to elevate it, has various limitations
Enzyme Regulation
Substrate Availability
Reversible Inhibitions
Feedback inhibition
Irreversible (Suicide) Inhibition
EX - GLUT4 glucose uptake (PKB/AKT dependent)... Insulin binds t…
Competitive (stains and HMG-CoA reductase)... Noncompetitive (al…
usually noncompetitive (hydrophobic amino acid, pyrimidine, p…
Aspirin => cyclo-oxygenase (inhibited) => prostaglandins... Peni…
Substrate Availability
EX - GLUT4 glucose uptake (PKB/AKT dependent)... Insulin binds t…
Reversible Inhibitions
Competitive (stains and HMG-CoA reductase)... Noncompetitive (al…
32 terms
Enzyme Regulation
Irreversible inhibitors
Reversible Inhibitors
Organophosphorus compounds
Aspirin (NSAID)
bind covalently (modify aa side chains at active site),progre…
bind by weak interactions, at equilibrium with enzyme (ki), e…
irreversible inhibitors inhibit Acetylcholinesterase by coval…
covalently modifies cycloxygenase preventing prostaglandin an…
Irreversible inhibitors
bind covalently (modify aa side chains at active site),progre…
Reversible Inhibitors
bind by weak interactions, at equilibrium with enzyme (ki), e…
25 terms
Enzyme Regulation
how are enzymes regulated?
isozyme (aka isoform)
LDH-5 vs LDH-1
allosteric control doesn't follow what
1. amount of enzyme... 2. enzyme activity... 3. substrate availabil…
different enzymes that catalyze the same rxn; expressed in di…
LDH-5 is M4 and seen in early development; LDH-1 is H4 and se…
Michaelis-Menten kinetics
how are enzymes regulated?
1. amount of enzyme... 2. enzyme activity... 3. substrate availabil…
isozyme (aka isoform)
different enzymes that catalyze the same rxn; expressed in di…
Enzyme regulation
Cervical nodes
Hilar nodes
Mediastinal nodes
Axillary nodes
Head, neck, pharynx
Lungs
Trachea, esophagus
Breast, upper limb, skin above umbilicus
Cervical nodes
Head, neck, pharynx
Hilar nodes
Lungs
Enzyme Regulation
3 Ways to Regulate Enzyme Activity
Reversible Inhibitors
Irreversible Inhibitors
Competitive Inhibition
1) At the level of gene expression - effecting enzyme concent…
Interact with an enzyme via noncovalent associations.
Interact with an enzyme via covalent associations... Ex: Penicil…
Competes with natural substrate for active site ... No product f…
3 Ways to Regulate Enzyme Activity
1) At the level of gene expression - effecting enzyme concent…
Reversible Inhibitors
Interact with an enzyme via noncovalent associations.
15 terms
Enzyme regulation
Hexose
G6Phosphatase
PFK1
FBPase
G6P inhibit
Glucose inhibit, glucagon stimulate cAMP to CREB to increase…
Activated by F26BP, ATP inhibits
inhibited by F26BP, stimulated by ATP
Hexose
G6P inhibit
G6Phosphatase
Glucose inhibit, glucagon stimulate cAMP to CREB to increase…
18 terms
Enzyme regulation
Mechanisms of enzyme regulation after…
Characteristics of covalent regulation
Regulation of enzyme synthesis
Regulation of Zymogen proteins
1) Zymogen activation- inactive protein is irreversibly modif…
speed... amplification of signal... energy input is required (ATP)
regulation of transcription of the enzyme... only specific tissu…
Amount of zymogen available... Amount of protease available... Acti…
Mechanisms of enzyme regulation after…
1) Zymogen activation- inactive protein is irreversibly modif…
Characteristics of covalent regulation
speed... amplification of signal... energy input is required (ATP)
9 terms
Enzyme regulation
Very Fast regulation
Rapid Reg: ... Noncovalent interactions
Competitive inhibition
Covalent interactions (reversible)
affect the enzymes that are already present... -noncovalent int…
-reversible activators and inhibitors --> bind to active site…
inhibitor competes for active site ... structurally resembles t…
Phosphorylation/Dephosphorylation
Very Fast regulation
affect the enzymes that are already present... -noncovalent int…
Rapid Reg: ... Noncovalent interactions
-reversible activators and inhibitors --> bind to active site…
27 terms
enzyme regulation
hexokinase I/II inhibitor(s)
hexokinase IV inhibitor(s)
hexokinase IV activator(s)
PFK-1 inhibitor(s)
G6P
F6P, GKRP
glucose, insulin (transcriptional)
ATP (stabilizes T state), citrate (enters cytosol thru transp…
hexokinase I/II inhibitor(s)
G6P
hexokinase IV inhibitor(s)
F6P, GKRP
Enzyme Regulation
Enzymes
Types of enzymes
Oxidoreductases
Transferases
Are bio catalysts that increase the rate of chemical reaction…
Oxidoreductases, transferases, hydrolases, lyases, isomerases…
Oxidation-reduction reaction. Ex: Lactate dehydrogenase
Groups transfer, Ex nucleoside monophosphate kinase (NMP Kina…
Enzymes
Are bio catalysts that increase the rate of chemical reaction…
Types of enzymes
Oxidoreductases, transferases, hydrolases, lyases, isomerases…
18 terms
Enzyme Regulation
enzyme specificity
specificity
"lock and key" hypothesis
"induced fit" hypothesis
ability of an enzyme to catalyze only one particular reaction
depends on the structural complementarity of enzyme and subst…
considers the enzyme to resemble a "lock" and the substrate a…
considers that the enzyme's active site is modified upon bind…
enzyme specificity
ability of an enzyme to catalyze only one particular reaction
specificity
depends on the structural complementarity of enzyme and subst…
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