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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…
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…
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
...
34 terms
Enzyme Regulation
Substrate Availability Regulating Enzy…
Mechanism of GLUT4 Mobilization
Types of Reversible Enzyme Inhibition
Statins
-Glucose (substrate) availability is controlled by number of…
-Insulin binds ligand and activates PKB/AKT kinase... -Kinase ph…
-Competitive... -Noncompetitive... -Mixed type
-Competitive inhibitors... -Targets the rate limiting step for c…
Substrate Availability Regulating Enzy…
-Glucose (substrate) availability is controlled by number of…
Mechanism of GLUT4 Mobilization
-Insulin binds ligand and activates PKB/AKT kinase... -Kinase ph…
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.…
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…
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
25 terms
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…
7 terms
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…
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…
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)…
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…
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
27 terms
Enzyme Regulation
1) Substrate Availability
2) Reverse Inhibition of Enzyme Activity
3) Irreversible Suicide Inhibition
Aspirin Mechanism
Glucose uptake into cells - GLUT4... ... Insulin activated movemen…
Competitive - Statins and HMG-COA reductase... Statins resemble…
Irreversible or suicide inhibition of enzymes occurs when the…
Acetosalicylic acid (aspirin) blocks the action of the enzyme…
1) Substrate Availability
Glucose uptake into cells - GLUT4... ... Insulin activated movemen…
2) Reverse Inhibition of Enzyme Activity
Competitive - Statins and HMG-COA reductase... Statins resemble…
8 terms
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
10 terms
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.
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)
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)…
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…
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…
46 terms
Enzymes and Enzyme regulation
oxidoreductase
transferase
hydrolase
lyase
catalyzes oxidation-reduction reaction
catalyzes transfer of C-, N-, or P-containing groups
catalyzes cleavage of bonds by addition of water
catalyzes cleavage of bonds by the addition of water
oxidoreductase
catalyzes oxidation-reduction reaction
transferase
catalyzes transfer of C-, N-, or P-containing groups
37 terms
Enzyme Regulation
Regulatory enzymes generally catalyze…
How can an enzyme be regulated? (4 ways)
2 binding sites for allosteric enzymes
When a ligand modulator binds to its b…
rate limiting
1. Allosteric... 2. Covalent (reversible)... 3. Proteolytic cleavag…
1. Active site for ligand... 2. Allosteric site for modulator
active site
Regulatory enzymes generally catalyze…
rate limiting
How can an enzyme be regulated? (4 ways)
1. Allosteric... 2. Covalent (reversible)... 3. Proteolytic cleavag…
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
19 terms
enzyme regulation
___________ availability: concentratio…
_________ inhibition: ... enzyme product…
____________ control:... effector directl…
______________ modification: ... another…
substrate
product
allosteric
covalent
___________ availability: concentratio…
substrate
_________ inhibition: ... enzyme product…
product
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…
39 terms
enzyme regulation
Hexokinase/Glucokinase- reaction it ca…
allosteric regulation of gluco/hexokin…
hormonal regulation of gluco/hexokinase
PFK-1: reaction it catalyzes
Step 1 in glycolysis: Glucose + ATP---> glucose-6-phosphate +…
hexokinase is feedback inhibited by glucose-6-phosphate
glucokinase is inducible and controlled in the liver by amoun…
step 3 in glycolysis: fructose-6-phosphate+ ATP--> ADP+ fruct…
Hexokinase/Glucokinase- reaction it ca…
Step 1 in glycolysis: Glucose + ATP---> glucose-6-phosphate +…
allosteric regulation of gluco/hexokin…
hexokinase is feedback inhibited by glucose-6-phosphate
30 terms
Enzyme Regulation
Anabolism
Catabolism
Alcohol Metabolism
Alcohol Metabolism Steps
Constructive metabolism; the process of building up larger mo…
Metabolic pathways that break down molecules, releasing energy.
Leads to a build up of NADH, which stimulates fatty acid synt…
Ethanol+NAD->Acetaldehyde+NADH... Acetaldehyde+NAD->Acetate+NADH
Anabolism
Constructive metabolism; the process of building up larger mo…
Catabolism
Metabolic pathways that break down molecules, releasing energy.
14 terms
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
22 terms
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…
35 terms
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…
15 terms
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…
9 terms
enzyme regulation
covalent modification
allosterism
conformational changes of allosteric e…
T-state
molecules can be used to reversibly and covalently modify enz…
molecule binds to enzyme somewhere besides the active site... un…
result in transitions between the T and R states
inactive
covalent modification
molecules can be used to reversibly and covalently modify enz…
allosterism
molecule binds to enzyme somewhere besides the active site... un…
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
8 terms
Enzyme Regulation
Zymogens
Positive allosteric regulation
Negative allosteric regulation
Five ways enzyme activity is regulated?
Inactive form of an enzyme for storage
Regulator binds to enzyme causing enzyme to become more active
Regulator binds to enzyme causing enzyme to turn off
Allosteric, zymogens, genetic, compartmentalization, phosphor…
Zymogens
Inactive form of an enzyme for storage
Positive allosteric regulation
Regulator binds to enzyme causing enzyme to become more active
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
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
19 terms
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
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…
8 terms
Enzyme regulation
Activation
Inhibition
Feedback control
Allosteric control
Process that starts or speeds up an enzymes activity
Stops or slows down an enzymes activity
Tells the first enzyme in a multi step reaction how fast to r…
Interaction when the binding of one substrate at one active s…
Activation
Process that starts or speeds up an enzymes activity
Inhibition
Stops or slows down an enzymes activity
30 terms
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…
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…
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
Allosteric regulation
Allosteric regulation
CTP
ATP
The binding of a regulator molecule to a protein affect its a…
Most instantaneous as it enables enzymes to directly monitor…
Allosteric inhibitor of ATCase
Competitive inhibitor of CTP; has no direct effect on the enz…
Allosteric regulation
The binding of a regulator molecule to a protein affect its a…
Allosteric regulation
Most instantaneous as it enables enzymes to directly monitor…
8 terms
Enzyme regulation
IICCELS
isozymes
Inhibition
Covalent modifications
mnemonic
pyruvate kinase 4, COX 1 and COX 2
ATP inhibits Pyruvate Kinase (alanine too)
phosphorylation- reversible. ... phoshporylate the liver pyruva…
IICCELS
mnemonic
isozymes
pyruvate kinase 4, COX 1 and COX 2
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 (…
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…
60 terms
Enzyme Regulation
Enzyme basic facts
Enzyme native conformation
Cofactors
Inorganic ions in enzymes
reaction catalyst of biological system... highly specialized ... hu…
denatured
non-protein additional components in enzymes
Fe2+, Mg2+, Mn2+, Zn2+
Enzyme basic facts
reaction catalyst of biological system... highly specialized ... hu…
Enzyme native conformation
denatured
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