1 / 33

Enzymes: Remarkable Biological Catalysts

Enzymes: Remarkable Biological Catalysts. Jianing Li Chemistry Department Columbia University April 14th,2007. The activity of an enzyme is responsible for the glow of the luminescent jellyfish. Basic Concepts. Enzyme Substrate Active Site Cofactor and coenzyme Inhibitor.

linh
Download Presentation

Enzymes: Remarkable Biological Catalysts

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Enzymes: Remarkable Biological Catalysts Jianing Li Chemistry Department Columbia University April 14th,2007

  2. The activity of an enzyme is responsible for the glow of the luminescent jellyfish

  3. Basic Concepts • Enzyme • Substrate • Active Site • Cofactor and coenzyme • Inhibitor

  4. What is an enzyme? • The catalyst of biological systems • The remarkable molecular device that determine the patterns of chemical reactions • Catalytic power and specificity • Mainly proteins, but ribozyme (RNA)

  5. What are the characteristics of enzymes? • Higher efficiency • Milder conditions • Greater reaction specificity • Capacity for regulation Factors influencing enzyme activity: pH, temperature, concentration of enzyme and substrate

  6. Why highly efficient?

  7. Catalytic power and specificity

  8. Enzymes and Cofactors • Most other enzymes are named for their substrates and for the reactions that they catalyze, with the suffix "ase" added. (ATPase ) • Many enzymes require cofactors for activity • Cofactors are small molecules or metal ions • Vitamins

  9. Cofactor in an enzymeFrom www.psc.edu

  10. Six major classes of enzymes • Oxidoreductases • Transferases • Hydrolases • Lyases • Isomerases • Ligases

  11. Active Sides

  12. How does an Enzyme Work?

  13. Lock-and–Key Model

  14. Induce-Fit Model

  15. Inhibitors

  16. If you want to know more about enzymes: • http://www.northland.cc.mn.us/biology1111/animations/enzyme.swf • http://ca.expasy.org/spdbv/text/getpc.com • http://biochem.ucl.ac.uk/bsm/enzymes/ • Biochemistry, 5th edition, Jeremy M. Berg etc.

  17. Exercise: • Surf in an enzyme data base • Find an example for each class of enzyme • Think about the PDB ID, Name, Class, Reaction, Cofactor

  18. Let’s play a game

  19. Question 1.1 • Which statement is correct about enzyme classification? • Enzymes are usually classified on their structures. • Enzymes are usually classified on their mechanism • Enzymes are classified into 5 classes • Enzymes are classified into 7 classes Go back

  20. Question 1.2 • Enzymes are sensitive to these following factors except: • pH value • Temperature • Concentration of enzyme and substrate • Light Go back

  21. Question 1.3 • The molecules which decrease the enzyme activity are called: • Activators • Initiators • Indicators • Inhibitors Go back

  22. Question 1.4 • If we want to deactivate an enzyme, we do these except: • Increase the temperature • Add inhibitors • Remove the coenzyme • Add salt solution Go back

  23. Question 2.1 • Which statement is not the character of enzyme? • High efficiency • Mild condition • Specificity • Turnover the reaction Go back

  24. Question 2.2 • Enzymes don’t change quantitatively in the biochemical reactions, but they change in structures temporarily. • This statement is false • This statement is completely true • This statement is only true partially Go back

  25. Question 2.3 • How do animals make light? • They heat themselves • They eat special chemicals which can give off light • They make light from an enzyme-catalyzed reaction • All are correct Go back

  26. Question 2.4 • If you are going to do an experiment, but it is very slow at room temperature. Which way can speed it up most? • Increase the temperature • Increase the external pressure • Add enzymes • Add inhibitors Go back

  27. Question 3.1 • There are __ kinds of inhibitor(s)? • 6 • 5 • 2 • 1 Go back

  28. Question 3.2 • Cofactors aren’t: • Enzymes • Metal ions • Small molecules • Vitamins Go back

  29. Question 3.3 • Which of the following statement is correct? • Enzymes are specific • The “lock-key” model shows that a enzyme is flexible in structure and change itself to accommodate the substrate • Enzymes don’t change activation energy Go back

  30. Question 3.4 • Which statement is nor correct? • All the enzymes are proteins • Not all the enzymes are proteins • Most enzymes are proteins • No enzyme is protein Go back

More Related