Enzymes

What are Enzymes? Enzymes are proteins that speed up chemical reactions. They cause change, so they are also called catalysts. –Reactions can occur without enzymes, but they may take a really long time. Enzymes lower the amount of energy needed for the reaction to take place. – ymes/prox-orien.swfhttp:// ymes/prox-orien.swf

Enzyme Labeling

What can enzymes do? Some enzymes can break down substances into smaller parts. Other enzymes can build substances that cells need.

There are thousands of enzymes! Why? Each enzyme is specific for one substrate (the substance it binds to). The enzyme and substrate fit together like a lock and a key. When the substrate and enzyme bind, the enzyme actually changes its shape a little.

Enzymes are “green”! Once an enzyme has finished with helping one reaction, it’s ready for another. Enzymes are reusable.

Do enzymes always work? NO - There are two factors that can denature enzymes, or alter the enzyme’s shape and stop it from doing its job. They are: –Temperature –pH nch/lab2/ph.html nch/lab2/ph.html (Denatured enzyme)

Has the enzyme been destroyed? “Denatured” does not mean the enzyme has been destroyed. It has simply lost its shape. Enzymes can be “renatured.” If they are returned to normal conditions, they will regain function.

When do enzymes work best? Enzymes work best at an optimal temperature and pH level specific for that enzyme. Not all enzymes function at the same temp. or pH. Amylase- enzyme in mouth Pepsin- enzyme in stomach Arginase- enzyme in intestines Which ones work at the same pH?

How do you know it’s an enzyme? ClassFunction 1. OxidoreductaseCatalyse redox reactions 2. Transferases Catalyse transfer of a molecular group from one molecule to another 3. Hydrolases Catalyse bond cleavage by the introduction of water 4. Lysases Catalyse reactions involving the removal of a group to form a double bond or addition of a group to a double bond 5. Isomerases Catalyse reactions involving intramolecular rearrangements 6. Ligases/Synthesases Catalyse reactions joining together two molecules What do all these enzyme names have in common?

More Enzyme Animations wkey=1879aed110525c185ff3http:// wkey=1879aed110525c185ff3 port.com/ /lib/ /Animations/Enzyme_activity.htmlhttp:// port.com/ /lib/ /Animations/Enzyme_activity.html hill.com/sites/ /student_view0/chapte r2/animation__how_enzymes_work.htmlhttp://highered.mcgraw- hill.com/sites/ /student_view0/chapte r2/animation__how_enzymes_work.html