Enzymes

EnzymesEnzymes

ApplesApples

Take a bite of your apple. Now turn your Take a bite of your apple. Now turn your apple 180apple 1800. 0. Take another bite.Take another bite.

On one bite of the apple, apply lemon juice to On one bite of the apple, apply lemon juice to the entire flesh surface.the entire flesh surface.

Avoid getting lemon juice on the skin.Avoid getting lemon juice on the skin.Wipe off any juice that has come into Wipe off any juice that has come into contact with skin.contact with skin.

Do nothing to the other bite of the apple.Do nothing to the other bite of the apple.

Place your apple out of the way…Place your apple out of the way…we will come back to them later on.we will come back to them later on.

Once Upon a Time…Once Upon a Time…

Louis Pasteur1860Fermentation

Edward Buchner1897Enzymes can function independently

J.B. Sumner1926Isolated urease from jack beanFirst to identify as protein

Why Do We Need Enzymes?Why Do We Need Enzymes?

Chemical reactions are how cells function.Chemical reactions are how cells function.

Chemical reactions take time. Tend to be very Chemical reactions take time. Tend to be very slow. slow.

For cells to work properly, many chemical For cells to work properly, many chemical reactions must happen in a short time.reactions must happen in a short time.

Enzymes speed up chemical reactions.Enzymes speed up chemical reactions.

Used in all chemical reactions in living things.Used in all chemical reactions in living things.

With out enzymes, With out enzymes, we would not be living!we would not be living!

What is an Enzyme?What is an Enzyme?

EnzymesEnzymes are proteins that provide are proteins that provide function to the cell.function to the cell.

Remember: Remember: Proteins are complex chains of organic Proteins are complex chains of organic compounds called amino acidscompounds called amino acids

Provide structure, function, and regulation Provide structure, function, and regulation of animal and plant cellsof animal and plant cells

Enzymes are Enzymes are catalysts.catalysts.Speed up chemical reactionsSpeed up chemical reactions

By lowering energy of activationBy lowering energy of activation

No permanent chemical No permanent chemical modifications modifications

as a result of participationas a result of participation

Can be used over and Can be used over and

over againover again

End is “- ase”End is “- ase”

What is a Substrate?What is a Substrate?

SubstratesSubstrates are compounds in the cell are compounds in the cell that are going to react chemically.that are going to react chemically.

Enzymes are Enzymes are highly specifichighly specific for their for their substrate.substrate.

Generally, there is one specific enzyme Generally, there is one specific enzyme for each specific chemical reaction.for each specific chemical reaction.

Enzymes and ReactionsEnzymes and Reactions

Activation energyActivation energy: small amount of energy needed to : small amount of energy needed to get the reaction going (camp fire).get the reaction going (camp fire).

Enzymes bring together the chemicals that are going Enzymes bring together the chemicals that are going to react and lowers the activation energy necessary to to react and lowers the activation energy necessary to get the reaction underwayget the reaction underway

Lock and Key AnalogyLock and Key Analogy

Induced Fit TheoryInduced Fit Theory

Active site: Is the place on the enzyme where the substrates fit.

Induced Fit Theory: updated Lock and key concept. States that when reactants are brought together, they reach a transition state which allows the reaction to proceed. Not as rigid.

Degradation and SynthesisDegradation and Synthesis

Degradation = large molecule broken down into a smaller ones

Synthesis = combination of several smaller molecules into a a large one

How Enzymes Work:How Enzymes Work:AnimationAnimation

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/ahttp://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.htmnimation__how_enzymes_work.htm

McGraw-Hill site will be pre-loaded onto the computer to be ready to play McGraw-Hill site will be pre-loaded onto the computer to be ready to play when this slide comes up.when this slide comes up.

What Effects Enzyme Activity?What Effects Enzyme Activity?

pH:Every enzyme has a small optimal pH range. Higher or lower pH disrupts chemical bonds changing the shape of the enzyme.

Temperature:Environments hotter than the enzyme’s optimal temperature cause the enzyme to denature (break down). Cold Temperature slows down enzyme activityBy decreasing molecular motion.

Metabolic EnzymesMetabolic Enzymes

Responsible for catalyzing biochemical Responsible for catalyzing biochemical reactions required to maintain life. reactions required to maintain life.

Exist throughout the entire body.Exist throughout the entire body.

Two categories of metabolic enzymes:Two categories of metabolic enzymes:CatabolicCatabolic - enzymes that break down large - enzymes that break down large moleculesmoleculesAnabolicAnabolic - enzymes that construct complex - enzymes that construct complex molecules from smaller pieces, such as molecules from smaller pieces, such as proteins from amino acids.proteins from amino acids.

Digestive EnzymesDigestive Enzymes

Digestive enzymes are catabolic enzymes Digestive enzymes are catabolic enzymes responsible for breaking down food into responsible for breaking down food into nutrients and energy.nutrients and energy.

They occur primarily in the mouth, stomach, They occur primarily in the mouth, stomach, and small intestine.and small intestine.

They are secreted by salivary glands, glands They are secreted by salivary glands, glands in the stomach, glands in the small intestine in the stomach, glands in the small intestine and the pancreas (largest producer of and the pancreas (largest producer of enzymes in the body).enzymes in the body).

Now…Back to Those Apples!Now…Back to Those Apples!

Do you notice any differences between Do you notice any differences between the two halves?the two halves?

If so, what are the differences?If so, what are the differences?

What caused the change/ if any?What caused the change/ if any?

Fruit BrowningFruit Browning

When an apple is cut or bitten into, cells When an apple is cut or bitten into, cells beneath the fruit’s skin are damaged and beneath the fruit’s skin are damaged and exposed to oxygen.exposed to oxygen.

An enzyme called polyphenol oxidase (also An enzyme called polyphenol oxidase (also called tyrosinase) contained in the cells is called tyrosinase) contained in the cells is exposed to and reacts with the oxygen in the exposed to and reacts with the oxygen in the air, causing the bruised appearance.air, causing the bruised appearance.

The citric acid in lemon juice denatures the The citric acid in lemon juice denatures the enzyme rendering it ineffective.enzyme rendering it ineffective.

Enzyme Vocabulary ReviewEnzyme Vocabulary Review

EnzymeEnzymeSubstrateSubstrateCatalystCatalystActivation energyActivation energyLock and Key AnalogyLock and Key AnalogyInduced Fit TheoryInduced Fit TheoryDegradationDegradationSynthesisSynthesisDenaturedDenaturedCatabolicCatabolicAnabolicAnabolic