ENZYMES

ENZYMESA type of Protein

MADE UP OF WHAT? A folded chain of amino acids

In living things they act asCatalysts

molecules that are used to speed up a chemical reaction without being changed in the reaction; the enzyme can be used over and over again

ENZYMESAre not SubstratesAre not ReactantsAre not Products

The participate in the reaction, but don’t change and can be reused (this is why they are “over the arrow”).

WHEN WE EAT ENZYMES…. We can’t use them…what has to happen first?

Eat enzymes??? If you eat anything that was, at one

point, a living cell or part of a living organism, you ARE eating enzymes!

ENZYMES (IN OUR BODIES)Break down enzymes (like any protein) in the digestive system.

Our enzymes are made by assembling these amino acids to form “human” proteins

Enzyme Activity Demo

ENZYMESAre needed for all chemical reactions includingDehydration synthesis and Hydrolysis

Provide the right “setting” for the chemical reaction

HOW DO ENZYMES WORK? Orient the substrate molecules correctly

Increase the likelihood a reaction will occur!

Enzyme Demo

ACTIVATION ENERGYEnzymes make it easier for substrates to reactThis is how the activation energy is

loweredActivation energy

The amount of energy needed to convert reactants into products

This is the “cost of the reaction”The enzyme is a “coupon”

ENERGY PLOT

Progress of the reaction

CHEMICAL REACTIONSSome chemical reactions release energyWhat has more energy, product or

reactants? What type of reaction is this?

Some reactions require energy inputAnswer the two questions above

again!

HOW DO ENZYMES WORK?

CATABOLISM ANABOLISM

LABEL THE PARTS (ENZYME IS BLUE)

Active Site

Substrate (Reactant)

Products

Enzyme is unchanged

C A + B enzyme

ANABOLIC REACTION

A + B C enzyme

THE CATALYTIC CYCLE OF AN ENZYME

Breakdown of Sucrose to Glucose and Fructose Using Sucrase

BUILDING REACTIONS USE….

Breakdown reactions ………

Using different words for the same event…..

SPECIFICITY OF ENZYMESEnzymes are EXTREMELY specific

There is a unique enzyme for EVERY substrate that reacts in the body

Each enzyme’s active site will ONLY fit one specific substrate

LOCK AND KEY MODEL

LOCK AND KEY (ACTUAL SHAPE)

INDUCED FIT THEORY -ENZYMES

ACTIVE SITEpart of an enzyme where substrates bind and undergo a chemical reaction

If this location is changed (damaged, mutated, etc. , the reaction cannot take place.

WHAT IMPACTS ENZYMES Temperature

All enzymes have an optimal temperature.

Exceeding optimal may cause enzyme inactivation (denaturation) due to breakage of bonds in quaternary and tertiary structures.

WHAT IMPACTS ENZYMESpH

changing the concentration of H+ interferes with the bonds holding the protein in its folded shape.

Raising or lowering pH above or below optimal will cause denaturation.

OPTIMAL PHpH is?

changing the concentration of H+ interferes with the bonds holding the protein in its folded shape.

ENZYMES HAVE SPECIFIC PH

INTERPRETING ENZYME GRAPHS

What is the optimum temperature

for this enzyme?

INTERPRETING ENZYME GRAPHS

Would this make a good human

enzyme?

DENATURATION

Caused by high temperatures and pH changes

HOW FAST AN ENZYME WORKS ALSO DEPENDS ON:

Concentration of the Enzyme

Concentration of the Substrate (what it is putting together or taking apart).

SATURATION CURVEWhat does this tell us? Why does this happen?

COENZYMES AND COFACTORS

CoenzymesOrganic molecules such as vitamins

CofactorsInorganic molecules or ions such as Zn and

Cu Both attach to enzymes and improve chances that substrate will bind to the enzyme.

Cofactor animation

ENZYME INHIBITION Inhibit: shut down or suppress

Can be caused by outside molecule – drugs/poisons (poisons, drugs

Can be caused by inside molecule if your body wants to temporarily shut down a reaction

Why waste the energy?

EXAMPLES – EXTERNAL Cyanide inhibits one of the

enzymes in cellular respiration (oxidase)RESULT: less oxygen less ATP death

Penicillan works by inhibiting a bacterial enzyme involved in making the cell wall. The bacteria is unable to reproduce.

Nerve gas interferes with acetylcholinesterase

RESULT: acetylcholine cannot be hydrolyzed nerve signals cannot be passed from nerve cell to nerve cell.

EXAMPLE - INTERNAL Feedback inhibition in a biochemical pathways

Feedback inhibition uses the product concentration to stop “production”

COMPETITIVE INHIBITIONmolecules that are similar in shape

to the substrate bind to the active site and block the substrate; No chemical reaction can happen

Examples: Drugs and Insecticides

ANIMATION INHIBITION

NON-COMPETITIVE INHIBITIONmolecule binds to a part of the

enzyme and alters the shape of the active site; No chemical reaction