U1 LE6: For Further Study Metabolic Managers Enzymes

1. Enzymes are proteins They are built by organisms from the nutrients or biomolecules they take in Enzymes frequently end with the suffix “-ase” amylase, lactase, cellulase, sucrase

Each lock requires it’s own key Every chemical reaction has it’s own enzyme

2. Every chemical reaction requires its own enzyme Amylase - breaks down starch Sucrase – breaks down sucrose Lactase – breaks down lactose Lipase – breaks down fats Polymerase – Builds nucleic acids (DNA or RNA) from nucleotides Helicase – Unwinds the DNA strand

Is this enzyme performing catabolism or anabolism?

Is this enzyme performing catabolism or anabolism? Reactant + Reactant -----------> Product

3. Enzymes have specific shapes Enzymes can fold into different shapes based on the number of amino acids, the type of amino acids, the sequence of amino acids. Ex. Analogy 26 letters of the alphabet 20 amino acids Form different words Form different proteins Ex. Ship vs. shipmate – different number and type Ex. Ship vs. Hips – different sequence

Enzymes have specific shapes Lactase is an enzyme that breaks down the disaccharide lactose into glucose and galactose Only the molecule of lactose will fit into this enzyme Catabolic or Anabolic reaction? chemicalconnection.org.uk 8

Enzymes shapes can be very complex Enzymes shapes can be very complex . . this is a diagram of lactase folded www.10jahresib.ethz.ch/.../educational.html

4. Enzymes catalyze or increase the rate of reactions Enzymes speed up reactions by a million times It would take 50 years to digest one meal without enzymes Life could not exist without enzymes, because metabolism would come to a screeching halt

5. Enzymes speed up reactions by decreasing the amount of energy needed Enzymes speed up reactions by decreasing the amount of energy needed to start the reaction student.ccbcmd.edu

6. Enzymes are not used up or changed in a reaction

7A. Enzyme Destruction: Temperature can change it’s shape or denature the enzyme High temperatures Destroy the shape of enzymes – they can’t do their job Metabolic process cannot occur This is why heat stroke can kill you http://www.a2gov.org/government/safetyservices/emergencymanagement/PublishingImages/Heat%20Exhaustion%202.gif

Effect of Temperature on Enzyme Reaction Rate 30 86 40 104 50 122 The rate of enzyme catalyzed reactions will increase with increasing temperature (due to an increase of molecule collisions) until an optimum temperature is reached. Above the optimum temperature the enzyme changes shape and is denatured (destroyed).

7B. Enzyme Destruction: pH can change it’s shape or denature the enzyme An improper pH can destroy enzymes Enzymes that work in specific parts of the body, need to work at a specific pH Blood pH 7 – 7.45 Stomach pH 1-4 Intestine pH 8 Mouth pH 6.7-7

Effect of pH on Enzyme Reaction Rate Pepsin is an enzyme in the stomach and as a pH optimum of about 1.5. Salivary amylase and alakaline phosphatase have pH optima of 6 and 9 respectively.

http://staff.jccc.net/PDECELL/chemistry/phscale.gif

7C. Enzyme Destruction: Salinity can also denature enzymes

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Enzyme Review… 1. Biomolecule Group: Proteins 2. Every reaction has its own enzyme 3. Enzymes have specific shapes (based on amino acids) 4. Catalyze or speed up reactions 5. Increase the rate of reactions by decreasing the amount of energy needed 6. Enzymes can be reused for more reactions 7. High temperatures, salinity, or pH can destroy or denature (change its shape)