E NZYMES

A type of Protein MADE UP OF WHAT? A folded chain of amino acids In living things they act as Catalysts 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

E NZYMES Are not Substrates Are not Reactants Are not Products The participate in the reaction, but don’t change and can be reused (this is why they are “over the arrow”).

W HEN 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

E NZYMES Are needed for all chemical reactions including Dehydration synthesis and Hydrolysis Provide the right “setting” for the chemical reaction

H OW DO E NZYMES W ORK ? Orient the substrate molecules correctly Increase the likelihood a reaction will occur! Enzyme Demo

A CTIVATION ENERGY Enzymes make it easier for substrates to react This is how the activation energy is lowered Activation energy The amount of energy needed to convert reactants into products This is the “cost of the reaction” The enzyme is a “coupon”

E NERGY P LOT Progress of the reaction

C HEMICAL R EACTIONS Some chemical reactions release energy What has more energy, product or reactants? What type of reaction is this? Some reactions require energy input Answer the two questions above again!

H OW DO E NZYMES W ORK ? CATABOLISM ANABOLISM

L ABEL THE PARTS ( ENZYME IS BLUE ) Active Site Substrate (Reactant) Products Enzyme is unchanged C A + B enzyme

A NABOLIC R EACTION A + B C enzyme

T HE C ATALYTIC CYCLE OF AN ENZYME Breakdown of Sucrose to Glucose and Fructose Using Sucrase

B UILDING REACTIONS USE …. Breakdown reactions ……… Using different words for the same event…..

S PECIFICITY OF E NZYMES Enzymes 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

L OCK A ND K EY ( ACTUAL SHAPE )

I NDUCED F IT T HEORY -E NZYMES

A CTIVE S ITE part of an enzyme where substrates bind and undergo a chemical reactionenzymesubstrates chemical reaction If this location is changed (damaged, mutated, etc., the reaction cannot take place.

W HAT IMPACTS E NZYMES Temperature All enzymes have an optimal temperature. All enzymes have an optimal temperature. Exceeding optimal may cause enzyme inactivation (denaturation) due to breakage of bonds in quaternary and tertiary structures. Exceeding optimal may cause enzyme inactivation (denaturation) due to breakage of bonds in quaternary and tertiary structures.

W HAT I MPACTS E NZYMES pH 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.

O PTIMAL P H pH is? changing the concentration of H+ interferes with the bonds holding the protein in its folded shape.

E NZYMES HAVE SPECIFIC P H

I NTERPRETING E NZYME G RAPHS What is the optimum temperature for this enzyme ?

I NTERPRETING E NZYME G RAPHS Would this make a good human enzyme ?

D ENATURATION Caused by high temperatures and pH changes

H OW F AST AN E NZYME WORKS ALSO DEPENDS ON : Concentration of the Enzyme Concentration of the Substrate (what it is putting together or taking apart).

S ATURATION C URVE What does this tell us? Why does this happen ?

C OENZYMES AND C OFACTORS Coenzymes Organic molecules such as vitamins Cofactors Inorganic molecules or ions such as Zn and Cu Both attach to enzymes and improve chances that substrate will bind to the enzyme. Cofactor animation

E NZYME I NHIBITION 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?

E XAMPLES – 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.

E XAMPLE - INTERNAL Feedback inhibition in a biochemical pathwaysFeedback inhibition in a biochemical pathways Feedback inhibition uses the product concentration to stop “production”

C OMPETITIVE I NHIBITION molecules 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

N ON - COMPETITIVE I NHIBITION molecule binds to a part of the enzyme and alters the shape of the active site; No chemical reaction