Enzymes: Proteins that are used for chemical reactions Enzymes can either break up or put together substrates Enzymes are specific – only work on certain substances. Enzymes are catalysts that react on substrates Enzymes are NOT CHANGED in the reaction Textbook pages: 78-81 Figure 5-5 on pg. 80 You will be responsible for all definitions on pages 1 & 5 of the enzyme packet, and should be able to interpret the graphs on Page 3 of the packet.

Definitions: Proteins: Biochemical compounds (macromolecules) made up of long polymer chains of amino acids linked together Catalyst: A substance that causes a reaction to occur but does not get changed itself

Definitions: Substrate: A substance that the catalyst (enzyme) acts on Ex) Lactose = milk sugar (substrate) Lactase = breaks down lactose (enzyme) Active Site: The specific region of the enzyme that combines with the substrate

Lock and Key: The lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).

Lactose is a 2-unit sugar Lactose is a 2-unit sugar. Lactase breaks it into 2 individual sugars: glucose and galactose. Can it break down sucrose as well? Why or why not?

Factors that affect the rate of Enzyme Action: Enzymes work best at certain: Temperatures pH Concentrations (See Graphs- Page 3 of Enzyme Packet)

Factors that affect the rate of Enzyme Action: Temperature: There is an optimum (best) temperature that each enzyme works in . Increase temperature, increase molecule movement, increase rate of the reaction. Temperature too LOW, decrease the effect of the enzyme Temperature too HIGH- Protein Denatures (breaks down/changes shape)- the enzyme will not work.

Denatured Enzyme

Factors that affect the rate of Enzyme Action: pH: Enzymes work best at different pH levels depending on where they are. Page 4- Enzyme Packet: Relative Rate of Enzyme Action. pH Scale? Acidic = 0 – 6.9 Basic = 7.1 – 14 #3- Enzyme A- pH of the stomach? #4- Enzyme B- pH of the intestine?

Factors that affect the rate of Enzyme Action: Concentration: Increasing the amount of enzyme will increase the rate of reaction, but it will eventually level off- why? For the same reason, increasing the substrate concentration will increase the rate of reaction, but it will eventually level off.

SEE ALL GRAPHS ON PAGE 3 of the Enzyme Packet

Activation Energy The energy needed to start a chemical reaction. Similar to rolling a boulder downhill, it is the chemical ‘push’ that gets a chemical reaction going. Enzymes lower the activation energy needed for chemical reactions. Less energy needed to start the reaction, can occur at lower temperatures.

Activation Energy Endothermic: Building

Activation Energy Exothermic: Breakdown

Enzyme Animation http://www.biotopics.co.uk/other/hienz.html http://www.kscience.co.uk/animations/anim_2.htm

How Enzymes Work The active site (location on the enzyme where the substrate fits and the reaction takes place) on the enzyme attaches to a substrate molecule While attached to the substrate, the enzyme either breaks or makes a bond, resulting a change to the substrate Ex) Carbohydrate broken into sugars Amino acids bonded to make protein The enzyme is not changed during the reaction and is free to break-down more substrates

CAPT LAB: ENZYMES Comparing the effectiveness of cellulase and pectinase in making juice. You will investigate which enzyme or combination of enzymes will remove more juice during the process of making apple juice from applesauce . Once you complete the lab, you will evaluate which enzyme will be the most cost effective plan to use in juice production.

CELLULOSE Large carbohydrate Composes the cell walls of plants Tough and fibrous – provides structure to plants

CELLULASE The enzyme that breaks down cellulose The optimum pH generally lies between 4 and 5

Pectin Large carbohydrate found in plant cell walls Sticky substance used to bind plant cell walls to each other and hold cellulose in place

Pectinase Enzyme that breaks down the pectin in plant cells Used to produce fruit juice and wine Optimum pH is 4-5

CAPT Lab: Cellulase v. Pectinase Enzymes? Pectinase and Cellulase Substrates? Apple Sauce

CAPT LAB: Purpose To determine which enzyme, or combination of enzymes, will produce the most juice for the least cost