enzymes enzyme structure enzyme enzymes are proteins that speed up chemical reactions. (catalyst)...

15
ENZYMES ENZYMES

Upload: roy-randall

Post on 22-Dec-2015

239 views

Category:

Documents


3 download

TRANSCRIPT

Page 1: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

ENZYMESENZYMES

Page 2: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

ENZYME STRUCTUREENZYME STRUCTURE

Page 3: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

ENZYMEENZYME

Enzymes are proteins that speed up chemical Enzymes are proteins that speed up chemical reactions. (catalyst)reactions. (catalyst)

Enzymes do not change when they perform their Enzymes do not change when they perform their function, and can be used over & over again.function, and can be used over & over again.

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

The shape of an enzyme determines its functionThe shape of an enzyme determines its function Their structure can be changed due to environmental Their structure can be changed due to environmental

factors and made inactive (denatured).factors and made inactive (denatured).

Page 4: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

ACTIVATION ENERGYACTIVATION ENERGY

Enzymes lower activation energy. (the energy required Enzymes lower activation energy. (the energy required to make a chemical reaction occur).to make a chemical reaction occur).

http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html

essentialchemistry/flash/activa2.swf Exergonic reactions- these release energyExergonic reactions- these release energy Endergonic reactions- these absorb free energy Endergonic reactions- these absorb free energy Energy coupling- the use of an exergonic process to Energy coupling- the use of an exergonic process to

drive an endergonic reaction. Ex: formation of ATP, drive an endergonic reaction. Ex: formation of ATP, from ADP. ATP is biological energy.from ADP. ATP is biological energy.

Page 5: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

THEORIESTHEORIES

Lock and Key- One specific enzyme fits into one Lock and Key- One specific enzyme fits into one specific substrate.specific substrate.

http://www.phschool.com/science/biology_place/labbench/lab2/binding.html

Induced fit- the enzyme fits to form the substrate.Induced fit- the enzyme fits to form the substrate.

Page 6: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

ENZYMEENZYME

Enzymes are very specific, they can only help Enzymes are very specific, they can only help one reaction. one reaction.

http://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html

Some enzymes can be used repeatedly on the Some enzymes can be used repeatedly on the same set of molecules to build long chains.same set of molecules to build long chains.

Page 7: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

FACTORS AFFECTING ENZYMESFACTORS AFFECTING ENZYMES

Certain enzymes work in a specific pH. Certain enzymes work in a specific pH. http://lpscience.fatcow.com/jwanamaker/animations/

Enzyme%20activity.html

Page 8: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

FACTORS Cont…FACTORS Cont…

Enzymes work in specific temperatures. As Enzymes work in specific temperatures. As temperature increases, enzyme activity increases temperature increases, enzyme activity increases unless it is too high, then it becomes denatured or unless it is too high, then it becomes denatured or destroyed. destroyed.

Page 9: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

FACTORS Cont…FACTORS Cont…

Small amounts of enzymes can react to a lot of substrate, but Small amounts of enzymes can react to a lot of substrate, but can limit the rate of the reaction, but does not decrease the can limit the rate of the reaction, but does not decrease the reaction.reaction.

Large amounts of enzymes will increase the reaction.Large amounts of enzymes will increase the reaction.

Page 10: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

COENZYMES & COFACTORSCOENZYMES & COFACTORS

These are not proteins. It is a These are not proteins. It is a coenzyme coenzyme (ex. (ex. Vitamins) if it is an Vitamins) if it is an organic moleculeorganic molecule and a and a cofactor if it is inorganiccofactor if it is inorganic. This allows a . This allows a reaction to take place. They maybe bound reaction to take place. They maybe bound tightly to the active site permanently or bond tightly to the active site permanently or bond loosely along with the substrate.loosely along with the substrate.

Page 11: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

Enzyme InhibitorsEnzyme Inhibitors Some chemicals inhibit the action of specific Some chemicals inhibit the action of specific

enzymes and is usually irreversible.enzymes and is usually irreversible. Noncompetitive inhibitors-Noncompetitive inhibitors- these do not these do not

compete directly with the active site. They compete directly with the active site. They impede enzymatic reactions by binding to impede enzymatic reactions by binding to another part of the enzyme. This will cause the another part of the enzyme. This will cause the enzyme to change shape and less active.enzyme to change shape and less active.

http://bio.winona.edu/berg/ANIMTNS/n-c-inan.htm

Page 12: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

Enzyme Inhibitors cont…Enzyme Inhibitors cont… competitive Inhibitors-competitive Inhibitors- these chemicals reduce these chemicals reduce

the productivity of enzymes by blocking the the productivity of enzymes by blocking the substrate from entering the active site.substrate from entering the active site.

http://www.northland.cc.mn.us/biology/Biology1111/animations/enzyme.swf

http://bio.winona.edu/berg/ANIMTNS/c-inhban.htm

http://www.wiley.com/college/pratt/0471393878/student/animations/enzyme_inhibition/enzyme_inhibition.swf

Page 13: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

Allosteric RegulationAllosteric Regulation

Some regulatory molecules behave like reversible Some regulatory molecules behave like reversible noncompetitive inhibitors. These molecules bind to noncompetitive inhibitors. These molecules bind to an allosteric site, which may either inhibit or an allosteric site, which may either inhibit or stimulate the enzymes activity.stimulate the enzymes activity.

http://www.stolaf.edu/people/giannini/flashanimat/http://www.stolaf.edu/people/giannini/flashanimat/enzymes/allosteric.swfenzymes/allosteric.swf

http://bio.winona.edu/berg/ANIMTNS/allostan.htmhttp://bio.winona.edu/berg/ANIMTNS/allostan.htm

Page 14: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

Feedback InhibitionFeedback Inhibition

When metabolic pathways are switched off by When metabolic pathways are switched off by an end-product.an end-product.

http://www.northland.cc.mn.us/biology/http://www.northland.cc.mn.us/biology/Biology1111/animations/enzyme.swfBiology1111/animations/enzyme.swf

Page 15: ENZYMES ENZYME STRUCTURE ENZYME Enzymes are proteins that speed up chemical reactions. (catalyst) Enzymes are proteins that speed up chemical reactions

CooperativityCooperativity

Molecules may stimulate the catalytic powers Molecules may stimulate the catalytic powers of an enzyme. If an enzyme has two or more of an enzyme. If an enzyme has two or more subunits, this interaction with one substrate subunits, this interaction with one substrate molecule triggers the same favorable molecule triggers the same favorable conformational change in all the subunits of conformational change in all the subunits of the enzyme.the enzyme.

http://www.northland.cc.mn.us/biology/http://www.northland.cc.mn.us/biology/Biology1111/animations/enzyme.swfBiology1111/animations/enzyme.swf