Chemistry 121(01) Winter 2009

1. Introduction to Organic Chemistry and Biochemistry Instructor Dr. UpaliSiriwardane (Ph.D. Ohio State) E-mail: upali@chem.latech.edu Office: 311 Carson Taylor Hall ; Phone: 318-257-4941; Office Hours: MTW 9:00 am - 11:00 am; TR 9:00 - 10:00 am & 1:00-2:00 pm. Chemistry 121(01) Winter 2009 December 19, Test 1 (Chapters 12-14) January 2 Test 1 (Chapters 15-16) February 6 (Chapters 17-19) February 27, (Chapters 20 & 22) March 2, 2009, Make Up Exam: Bring Scantron Sheet 882-E

2. Chapter 21. Enzymes and Vitamins Sections

3. Chapter 21. Enzymes and Vitamins 21.1 General Characteristics of Enzymes21.2 Nomenclature and Classification of Enzymes21.3 Enzyme Structure21.4 Models of Enzyme Action21.5 Enzyme Specificity21.6 Factors That Affect Enzyme Activity21.7 Enzyme Inhibition21.8 Regulation of Enzyme Activity: Allosteric Enzymes21.9 Regulation of Enzyme Activity: Zymogens21.10 Antibiotics That Inhibit Enzyme Activity21.11 Medical Uses of Enzymes21.12 Vitamins21.13 Water-Soluble Vitamins21.14 Fat-Soluble Vitamins

4. Chapter 21. Enzymes Nomenclature and Classification Activation Energy Enzyme-Substrate Interaction Cofactors and Coenzymes Effect of pH and Temperature Regulation of Enzyme Activity

5. BiologicalCatalysts Typically very large proteins Permit reactions to to “go” to conditions that the body can tolerate Can process millions of molecules per second Are very specific-react with one or only a few types of molecules (substrates).

6. Enzyme Nomenclature Naming is easy compared to other organic compounds Name is based on: -What it reacts with -how it reacts -add -ase- ending Examples lactase enzyme that reacts with lactose pyruvate decarboxylase remove carboxyl group from pyruvate

7. Classification of Enzymes • Oxidoreductases: catalyze oxidation-reduction. • Transferases: transfer of functional groups. • Hydrolases: catalyze hydrolysis reactions. • Lyases: catalyse the removal of chemical groups. • Isomerases: catalyze isomerization reactions. • Ligases: catalyze formation of chemical bonds, join two molecules

8. Effect of Enzyme on Activation Energy • Enzyme change how • a reaction will proceed. • This reduces the activation energy • It makes it easier

9. Effect of Enzyme on Activation Energy

10. Effect of Substrate Concentration • For non-catalyzed reactions Reaction rate increase with concentration • Enzyme catalyzed reactions Also increase but only to a certain point VmaxMaximum velocity At Vmax, the enzyme is working as fast as it can

11. Effect of Substrate Concentration

12. Characteristics of Enzyme Active Sites • Catalytic site Where the reaction actually occurs. • Binding site Area that holds substrate in proper place. Enzyme uses weak, non-covalent interactions to hold the substrate in place based on alkyl (R) groups of amino acids. Shape is complementary to the substrate and determines the specificity of the enzyme. Sites are pockets or clefts on enzyme surface.

13. Steps in Enzymatic Reactions • Enzyme and substrate combine to form a complex • Complex goes through a transition state -which is not quite substrate or product • A complex of the enzyme and the product is produced • Finally the enzyme and product separate All these steps are equilibria Lets review each step

14. The Players

15. Formation of Enzyme-substrate Complex

16. Formation of the Transition State

17. Formation of the Enzyme-Product Complex