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 -----------> ProductEnzyme

3. Enzymes have specific shapesEnzymes 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

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

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).

C F

30 86

40 104

50 122

7B. Enzyme Destruction:pH can change it’s shape or denature the enzyme

Blood pH 7 – 7.45 Stomach pH 1-4 Intestine pH 8 Mouth pH 6.7-7

An improper pH can destroy enzymes

Enzymes that work in specific parts of the body, need to work at a specific pH

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 alsodenature enzymes

Meet Milo, Larry, Ernest & the Rest

Enzyme Review…1. Biomolecule Group: Proteins2. Every reaction has its own enzyme3. Enzymes have specific shapes (based on amino acids)4. Catalyze or speed up reactions5. Increase the rate of reactions by decreasing the amount of energy needed6. Enzymes can be reused for more reactions7. High temperatures, salinity, or pH can destroy or denature (change its shape)