SlideShare a Scribd company logo
1 of 52
BCOR 011 Lecture 12
9/28/2005
ENZYMES
Last time…
-G reaction “can” go
spontaneous
But when will it go?
And at what rate?
Thermodynamics
Whether a reaction will occur
Kinetics
WHEN a reaction will occur
What governs WHEN a reaction will occur?
The tower of blocks falling is favorable
but when will it happen?
Oxidation of carbohydrate polymers (starch)
to carbon dioxide and water is favorable
but when will it happen?
Gasoline burning to carbon dioxide and water
is favorable
but when will it happen ?
For a Reaction to occur need to Destabilize Existing State
to INPUT ENERGY
Now In Transition
Potential
net
usable
energy
Destabilization
energy input
“Activation
Energy”
Potential
net
usable
energy
Need to INPUT ENERGY to Destabilize Existing State
In Transition After
Potential
net
usable
energy
net
usable
energy
released
Regain
Activation
Energy
Invested
What does activation energy represent?
For a Reaction to Occur…
- reactants must find each other,
- meet in proper orientation
- and hit with sufficient force
Productive
Collision
Many
Non-productive
Collisions
Needs of Typical
chemical reactions
- need large number of molecular collisions
- need collide violently enough to
break pre-existing bonds (not bounce)
- need high concentration to find each
other at significant rate
HEAT !
The energy profile for an exergonic reaction
Free
energy
Progress of the reaction
∆G < O
EA
Figure 8.14
A B
C D
Reactants
A
C D
B
Transition state
A B
C D
Products
Molecules with
sufficient
Energy (<5%)
Molecules with
sufficient
Energy (~40%)
Temp 1 Temp 2 EA
ENZYMES make reactions
easier to occur at
reasonable temperature
by
LOWERING the
ACTIVATION ENERGY
EA
of the reaction
Activation Energy
Energy necessary to overcome the status quo
G Thermodynamic
“favorablility”
EA
“ease” of
initiating reaction
G
EA
CATALYSTS:
promote a specific reaction
But are NOT consumed in the process
Key concepts:
Promotes - does not alter what would normally
occur thermodynamically
Specificity - promotes only one reaction, only
between specific reactants to give specific products
Reusable - regenerated in the process
ENZYMES are biological CATALYSTS
- usually PROTEINS
- sometimes RNA or
RNA/protein complexes
Hard path
Easy path
Enzymes work as catalysts
by providing an easy path to the same point
HOW?
How do Enzymes do it?
1. Enzymes have BINDING AFFINITY
for their reactants = Substrates
Brings substrates in close proximity: conc
Enzymes act as a Specific Platform
Have a very Specific 3-D Shape
With a Specific Arrangement
of Functional Groups
Flexible
OH
HO
+
HO
Polar
Nonpolar
Charged
Stabilized Interactions
-
HO
OH
HO
OH
+
HO
OH
SPECIFICITY is the Key to Enzyme Action
ENZYMES:
Bind ONLY specific things
Bind them ONLY in a
Specific 3-D Orientation
2. Enzymes ORIENT Substrates
always in productive orientation
Productive
Collision
Many
Non-productive
Collisions
ONLY Productive
Collisions
-
HO
OH
HO
OH
+
HO
OH
With just a little nudge, can’t help but react
3a. Physical Strain
3b.Chemical Strain
3. Enzymes cause BOND STRAIN
- destabilize existing bonds
“nutcracker effect”
The active site
– Is the region on the enzyme where the
substrate binds
Figure 8.16
Substate
Active site
Enzyme
(a)
Induced fit of a substrate
Figure 8.16 (b)
Enzyme- substrate
complex
Enzyme-substrate interactions
Fischer:
Lock & key
Koshland:
Induced fit
3a. Physical bond strain
Draw an quarter - an anvil
• The catalytic cycle of an enzyme
Substrates
Products
Enzyme
Enzyme-substrate
complex
1 Substrates enter active site; enzyme
changes shape so its active site
embraces the substrates (induced fit).
2 Substrates held in
active site by weak
interactions, such as
hydrogen bonds and
ionic bonds.
3 Active site (and R groups of
its amino acids) can lower EA
and speed up a reaction by
• acting as a template for
substrate orientation,
• stressing the substrates
and stabilizing the
transition state,
• providing a favorable
microenvironment,
• participating directly in the
catalytic reaction.
4 Substrates are
Converted into
Products.
5 Products are
Released.
6 Active site
Is available for
two new substrate
Mole.
Figure 8.17
3b. Chemical Bond Strain
tease the bond to fall apart
Chemical Bond Strain
Stabilize a
Fictitious
state
Cofactors
• Cofactors
– Are nonprotein enzyme helpers, eg Zn++
• Coenzymes
– Are organic cofactors
Non-polypeptide things at the active site
that help enzymes do their job
4. Enzymes “partake” in reactions
but are not consumed in them
Converts MANY “A’s” into “B’s”
H+
OH-
H+
Partakes: but start and end with the same enzyme config
Lysozyme
Lysozyme: kills bacteria
Works at pH 4-5 Why?
Enzymes:
1. Bring reactants (substrates) in close proximity
2. Align substrates in proper orientation
3. Can act as a Lever: a press or an anvil
small shape change translates to large force
4. Release products when reaction done
rebind more substrates
5. Many small steps, each easily achieved
rather than one huge leap
SUMMARY
You expect
me to
JUMP this?
No Problem
Dude
Enzymes carry out reactions in a series of
small steps rather than one energetic event
Reaction rates:
Example: H2O2-> H2O +O2
uncatalyzed –months
Fe+++ 30,000x faster
Catalase 100,000,000 x faster
Enzyme kinetics- kinetikos – moving
Rate
or
velocity
# made
per min
Substrate Conc
maximum velocity
Vmax
1/2 Vmax
Km
“substrate affinity”
An enzyme catalyzed rxn
Can be “saturated”
The lower the Km the better
the enzyme recognizes substrate
“finds it at low conc”
The higher the Vmax the more
substrate an enzyme can
process per min
(if substrate around)
“top speed”
“mpg”
Things that affect protein structure
often affect enzyme activity
temperature
pH
pH
0 1 2 3 4 5 6 7 8 9 10
0 20 40 60 80 100 º C
Enzyme regulation:
Activity controlled
Continually adjusted
Principal Ways of Regulating Enzymes
Competitive Inhibition
Allosteric Inhibition
Covalent Modification (phosphorylation)
-
HO
OH
HO
OH
+
HO
OH
HO
OH
Competitive
Inhibitors:
bind to active site
“unproductively”
and block
true substrates’
access
I
S1
S2
S & I bind to same site
Competitive inhibition
Allosteric Inhibitors
“other” “site”
Distorts the conformation
of the enzyme
Negative
allosteric
regulator
Allosteric inhibition
Positive allosteric regulators
Helps enzyme work better
promotes/stabilizes an “active” conformation
Allosteric activation
Allosteric regulators change the shape
conformation of the enzyme
Stabilized inactive
form
Allosteric activater
stabilizes active from
Allosteric enyzme
with four subunits
Active site
(one of four)
Regulatory
site (one
of four)
Active form
Activator
Stabilized active form
Allosteric activater
stabilizes active form
Inhibitor
Inactive form
Non-
functional
active
site
(a) Allosteric activators and inhibitors. In the cell, activators and inhibitors
dissociate when at low concentrations. The enzyme can then oscillate again.
Oscillation
Figure 8.20
A frequent regulatory modification
of enzymes
Phosphorylation
inactive
+ P
active
Phosphorylase kinase
Summary
1.enzymes are catalysts
2.Lower activation energy EA
3.Mechanism of action …
4.Enzyme kinetics- Vmax, Km
5.Regulation of enzyme activity
- competitive, allosteric
phosphorylation

More Related Content

Similar to 12 Enzymes 9 28 05.ppt

Similar to 12 Enzymes 9 28 05.ppt (20)

enzymes.pptx
enzymes.pptxenzymes.pptx
enzymes.pptx
 
Enzymes For Medical Students
Enzymes For Medical StudentsEnzymes For Medical Students
Enzymes For Medical Students
 
Catalysis
CatalysisCatalysis
Catalysis
 
Enzymes Updated 2023.pptx
Enzymes Updated 2023.pptxEnzymes Updated 2023.pptx
Enzymes Updated 2023.pptx
 
Catalysis- Physical Chemistry
Catalysis-  Physical ChemistryCatalysis-  Physical Chemistry
Catalysis- Physical Chemistry
 
ENZYME KINETICS
ENZYME KINETICSENZYME KINETICS
ENZYME KINETICS
 
Chemical reactions
Chemical reactionsChemical reactions
Chemical reactions
 
Ezyme-Honors5.ppt
Ezyme-Honors5.pptEzyme-Honors5.ppt
Ezyme-Honors5.ppt
 
Enzymes
EnzymesEnzymes
Enzymes
 
Enzymes dr.khushbu
Enzymes dr.khushbuEnzymes dr.khushbu
Enzymes dr.khushbu
 
A pc8metabolism ppt
A pc8metabolism pptA pc8metabolism ppt
A pc8metabolism ppt
 
Enzymes
EnzymesEnzymes
Enzymes
 
Enzyme Catalysis
Enzyme CatalysisEnzyme Catalysis
Enzyme Catalysis
 
02- Enzymes structure and function.pptx
02- Enzymes structure and function.pptx02- Enzymes structure and function.pptx
02- Enzymes structure and function.pptx
 
Phys 02 14b
Phys 02 14bPhys 02 14b
Phys 02 14b
 
Lecture 18.1- Rate Factors
Lecture 18.1- Rate FactorsLecture 18.1- Rate Factors
Lecture 18.1- Rate Factors
 
Enzymes lecture.ppt
Enzymes lecture.pptEnzymes lecture.ppt
Enzymes lecture.ppt
 
ENZYME BIOCHEMISTRY
ENZYME BIOCHEMISTRYENZYME BIOCHEMISTRY
ENZYME BIOCHEMISTRY
 
Enzynes
EnzynesEnzynes
Enzynes
 
Enzymes
Enzymes Enzymes
Enzymes
 

Recently uploaded

Fun for mover student's book- English book for teaching.pdf
Fun for mover student's book- English book for teaching.pdfFun for mover student's book- English book for teaching.pdf
Fun for mover student's book- English book for teaching.pdfhoangquan21999
 
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...dkNET
 
TEST BANK for Organic Chemistry 6th Edition.pdf
TEST BANK for Organic Chemistry 6th Edition.pdfTEST BANK for Organic Chemistry 6th Edition.pdf
TEST BANK for Organic Chemistry 6th Edition.pdfmarcuskenyatta275
 
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptx
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptxSaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptx
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptxPat (JS) Heslop-Harrison
 
MSCII_ FCT UNIT 5 TOXICOLOGY.pdf
MSCII_              FCT UNIT 5 TOXICOLOGY.pdfMSCII_              FCT UNIT 5 TOXICOLOGY.pdf
MSCII_ FCT UNIT 5 TOXICOLOGY.pdfSuchita Rawat
 
Costs to heap leach gold ore tailings in Karamoja region of Uganda
Costs to heap leach gold ore tailings in Karamoja region of UgandaCosts to heap leach gold ore tailings in Karamoja region of Uganda
Costs to heap leach gold ore tailings in Karamoja region of UgandaTimothyOkuna
 
A Scientific PowerPoint on Albert Einstein
A Scientific PowerPoint on Albert EinsteinA Scientific PowerPoint on Albert Einstein
A Scientific PowerPoint on Albert Einsteinxgamestudios8
 
Adaptive Restore algorithm & importance Monte Carlo
Adaptive Restore algorithm & importance Monte CarloAdaptive Restore algorithm & importance Monte Carlo
Adaptive Restore algorithm & importance Monte CarloChristian Robert
 
Efficient spin-up of Earth System Models usingsequence acceleration
Efficient spin-up of Earth System Models usingsequence accelerationEfficient spin-up of Earth System Models usingsequence acceleration
Efficient spin-up of Earth System Models usingsequence accelerationSérgio Sacani
 
Manganese‐RichSandstonesasanIndicatorofAncientOxic LakeWaterConditionsinGale...
Manganese‐RichSandstonesasanIndicatorofAncientOxic  LakeWaterConditionsinGale...Manganese‐RichSandstonesasanIndicatorofAncientOxic  LakeWaterConditionsinGale...
Manganese‐RichSandstonesasanIndicatorofAncientOxic LakeWaterConditionsinGale...Sérgio Sacani
 
VILLAGE ATTACHMENT For rural agriculture PPT.pptx
VILLAGE ATTACHMENT For rural agriculture  PPT.pptxVILLAGE ATTACHMENT For rural agriculture  PPT.pptx
VILLAGE ATTACHMENT For rural agriculture PPT.pptxAQIBRASOOL4
 
X-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
X-rays from a Central “Exhaust Vent” of the Galactic Center ChimneyX-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
X-rays from a Central “Exhaust Vent” of the Galactic Center ChimneySérgio Sacani
 
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...yogeshlabana357357
 
Electricity and Circuits for Grade 9 students
Electricity and Circuits for Grade 9 studentsElectricity and Circuits for Grade 9 students
Electricity and Circuits for Grade 9 studentslevieagacer
 
GBSN - Biochemistry (Unit 3) Metabolism
GBSN - Biochemistry (Unit 3) MetabolismGBSN - Biochemistry (Unit 3) Metabolism
GBSN - Biochemistry (Unit 3) MetabolismAreesha Ahmad
 
Heads-Up Multitasker: CHI 2024 Presentation.pdf
Heads-Up Multitasker: CHI 2024 Presentation.pdfHeads-Up Multitasker: CHI 2024 Presentation.pdf
Heads-Up Multitasker: CHI 2024 Presentation.pdfbyp19971001
 
NUMERICAL Proof Of TIme Electron Theory.
NUMERICAL Proof Of TIme Electron Theory.NUMERICAL Proof Of TIme Electron Theory.
NUMERICAL Proof Of TIme Electron Theory.syedmuneemqadri
 
PARENTAL CARE IN FISHES.pptx for 5th sem
PARENTAL CARE IN FISHES.pptx for 5th semPARENTAL CARE IN FISHES.pptx for 5th sem
PARENTAL CARE IN FISHES.pptx for 5th semborkhotudu123
 
Factor Causing low production and physiology of mamary Gland
Factor Causing low production and physiology of mamary GlandFactor Causing low production and physiology of mamary Gland
Factor Causing low production and physiology of mamary GlandRcvets
 

Recently uploaded (20)

Fun for mover student's book- English book for teaching.pdf
Fun for mover student's book- English book for teaching.pdfFun for mover student's book- English book for teaching.pdf
Fun for mover student's book- English book for teaching.pdf
 
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...
dkNET Webinar: The 4DN Data Portal - Data, Resources and Tools to Help Elucid...
 
TEST BANK for Organic Chemistry 6th Edition.pdf
TEST BANK for Organic Chemistry 6th Edition.pdfTEST BANK for Organic Chemistry 6th Edition.pdf
TEST BANK for Organic Chemistry 6th Edition.pdf
 
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptx
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptxSaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptx
SaffronCrocusGenomicsThessalonikiOnlineMay2024TalkOnline.pptx
 
MSCII_ FCT UNIT 5 TOXICOLOGY.pdf
MSCII_              FCT UNIT 5 TOXICOLOGY.pdfMSCII_              FCT UNIT 5 TOXICOLOGY.pdf
MSCII_ FCT UNIT 5 TOXICOLOGY.pdf
 
Costs to heap leach gold ore tailings in Karamoja region of Uganda
Costs to heap leach gold ore tailings in Karamoja region of UgandaCosts to heap leach gold ore tailings in Karamoja region of Uganda
Costs to heap leach gold ore tailings in Karamoja region of Uganda
 
A Scientific PowerPoint on Albert Einstein
A Scientific PowerPoint on Albert EinsteinA Scientific PowerPoint on Albert Einstein
A Scientific PowerPoint on Albert Einstein
 
Adaptive Restore algorithm & importance Monte Carlo
Adaptive Restore algorithm & importance Monte CarloAdaptive Restore algorithm & importance Monte Carlo
Adaptive Restore algorithm & importance Monte Carlo
 
Efficient spin-up of Earth System Models usingsequence acceleration
Efficient spin-up of Earth System Models usingsequence accelerationEfficient spin-up of Earth System Models usingsequence acceleration
Efficient spin-up of Earth System Models usingsequence acceleration
 
Manganese‐RichSandstonesasanIndicatorofAncientOxic LakeWaterConditionsinGale...
Manganese‐RichSandstonesasanIndicatorofAncientOxic  LakeWaterConditionsinGale...Manganese‐RichSandstonesasanIndicatorofAncientOxic  LakeWaterConditionsinGale...
Manganese‐RichSandstonesasanIndicatorofAncientOxic LakeWaterConditionsinGale...
 
VILLAGE ATTACHMENT For rural agriculture PPT.pptx
VILLAGE ATTACHMENT For rural agriculture  PPT.pptxVILLAGE ATTACHMENT For rural agriculture  PPT.pptx
VILLAGE ATTACHMENT For rural agriculture PPT.pptx
 
X-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
X-rays from a Central “Exhaust Vent” of the Galactic Center ChimneyX-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
X-rays from a Central “Exhaust Vent” of the Galactic Center Chimney
 
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...
Soil and Water Conservation Engineering (SWCE) is a specialized field of stud...
 
Electricity and Circuits for Grade 9 students
Electricity and Circuits for Grade 9 studentsElectricity and Circuits for Grade 9 students
Electricity and Circuits for Grade 9 students
 
Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...
Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...
Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...
 
GBSN - Biochemistry (Unit 3) Metabolism
GBSN - Biochemistry (Unit 3) MetabolismGBSN - Biochemistry (Unit 3) Metabolism
GBSN - Biochemistry (Unit 3) Metabolism
 
Heads-Up Multitasker: CHI 2024 Presentation.pdf
Heads-Up Multitasker: CHI 2024 Presentation.pdfHeads-Up Multitasker: CHI 2024 Presentation.pdf
Heads-Up Multitasker: CHI 2024 Presentation.pdf
 
NUMERICAL Proof Of TIme Electron Theory.
NUMERICAL Proof Of TIme Electron Theory.NUMERICAL Proof Of TIme Electron Theory.
NUMERICAL Proof Of TIme Electron Theory.
 
PARENTAL CARE IN FISHES.pptx for 5th sem
PARENTAL CARE IN FISHES.pptx for 5th semPARENTAL CARE IN FISHES.pptx for 5th sem
PARENTAL CARE IN FISHES.pptx for 5th sem
 
Factor Causing low production and physiology of mamary Gland
Factor Causing low production and physiology of mamary GlandFactor Causing low production and physiology of mamary Gland
Factor Causing low production and physiology of mamary Gland
 

12 Enzymes 9 28 05.ppt