∆G is negative Spontaneous Releases energy

1. ∆G is negative • Spontaneous • Releases energy

3. Active site - area with specific shape and correct amino acids needed to catalyze a reaction. Substrate – molecule bound to the active site that undergoes a reaction catalyzed by the enzyme

5. SPECIFICITY • How selective an enzyme is for a substrate or reaction. • High Specificity – ie. Thrombin • Low Specificity – ie. Papain

6. Thrombin clips two peptides from fibrinogen. This produces the fibrin monomer with exposed polymerization sites that can bind to other fibrin monomers. The monomers polymerize to form a loose clot.

7. Used as meat tenderizer • Treatment for jellyfish, bee and wasp stings • Used in contact lens solutions • Breaks down the protein in toxins, venoms and bacteria

10. Factors Affecting Activity • Enzyme concentration – the more enzyme present, the faster substrate reacts.

11. Increasing substrate concentration – increases the reaction rate until enzymes become saturated (Vmax).

12. Temperature/pH – enzymes have an optimum temperature and pH above which they begin to denature. /pH /pH

13. 1 2 6 4 5 3 Feedback – Regulation by end product of a reaction on an earlier step

14. ALLOSTERIC CONTROL Regulator

15. ENZYME INHIBITION • Reversible • Noncompetitive – Inhibitor does not bind at the active site (ie allosteric control) • Competitive – Inhibitor binds at the active site

16. Competitive Inhibition

18. Treatment of HIV With AZT

19. Competitive Inhibition Noncompetitive Inhibition

20. Irreversible Inhibition • Inhibitor binds at active site and forms covalent bond with amino acid side groups involved in catalysis. • Most toxins and poisons • Many pharmaceuticals

21. Heavy Metal Poisoning (Hg and Pb) -CH2-SH + Hg or Pb -CH2-S-Hg Pb Lead poisoning may have caused years of chronic illness in composer Ludwig van Beethoven and may have contributed to his death. Chemical analysis experts found unusually high levels of lead in strands of Beethoven's hair.

22. Lead in the Environment • Homes built prior to 1977 are likely to contain lead-based paint. • Soil near heavily-used streets and roads may contain lead because lead was used in gasoline until the 1970’s. • Lead may get into drinking water from materials used in plumbing, such as pipes. • Lead-glazed or lead-painted pottery, leaded crystal, and some inks

23. Mercury in the Environment Predator fish including tuna, mackeral, shark and swordfish “Mad as a Hatter” was a common expression in the 1800’s.

24. -CH2-OH Nerve Gases + Nerve Gas (X) -CH2-O-X Binds to the active site of acetylcholinesterase so acetylcholine is not broken down to acetyl CoA and choline, acetylcholine builds up in the synapse and jams nerves in the "on" position so they constantly signal muscles to contract.

25. -CH2-OH + -CH2-O-

26. Antibiotics All penicillin derivatives inhibit bacterial cell wall synthesis. If cell walls are improperly made it allows water to flow into the cell causing it to burst. The structure of a complex between penicillin G and the Streptomyces transpeptidase.

27. ZYMOGENS • Enzyme made in inactive form • Change to the enzyme makes it active • Digestion and blood coagulation

28. Thrombin clips two peptides from fibrinogen. This produces the fibrin monomer with exposed polymerization sites that can bind to other fibrin monomers. The monomers polymerize to form a loose clot.

29. Genetic Control Best for adapting to environmental or developmental changes