1. Functional Diversity of Proteins u Catalysis: Enzymes: amylase, pepsin, lipase u Transport: hemoglobin, serum albumin u Nutrient and Storage: egg albumin, zein u Movement, Contraction: myosin, actin u Structure: keratin, collagen u Defense: antibodies, fibrinogen u Regulation: hormones (insulin), repressors

2. Protein Classification by Function Structure Regulation Motion Regulation Transport Defense Catalysis Missing Function?Storage

3. Classification of Proteins By Shape Fibrous -insoluble in water Functions: structure, motion High percentage of nonpolar amino acids Globular -usually soluble in water Functions: transport, catalysis, storage Higher percentage of polar and charged amino acids

4. Classification of Proteins By Composition Simple contain only amino acids Examples: amylase, pepsin Conjugated - contain something besides amino acids Examples: Hemoglobin - contains iron Immunoglobin - contains carbohydrate Lactate dehydrogenase - contains niacin

5.  -carbon  -amino group  -carboxyl group side chain

7. Nonpolar Amino Acids

8. Polar, Uncharged Amino Acids

9. Polar, Charged Amino Acids Negatively-charged Positively-charged

10. Amino Acid Classification: Functional Group Alcohol Amide Carboxylic Acid Sulfhydryl Threonine (Thr)Serine (Ser) Cysteine (Cys) Aspartic Acid (Asp) Glutamic Acid (Glu) Asparagine (Asn) Glutamine (Gln)

13.  -carbon  -amino group  -carboxyl group side chain

14. Amino Acid Titration Isoelectric pH Net Charge 0 Below Isoelectric pH Net Charge + Above Isoelectric pH Net Charge –

15. Titration of Glycine Isoelectric pH = 6.0

16. Titration of Glutamic Acid Isoelectric pH = 3.2

17. Titration of Histidine Isoelectric pH = 7.6

18. Electrophoresis of Amino Acid Mixture at pH 6 Alanine, Arginine, Aspartic Acid At pH 6 Alanine (pI = 6)Net charge = 0 Aspartic Acid (pI = 2.8) Net charge is – Arginine (pI = 10.8)Net charge is +

19. Paper Chromatography of Amino Acids polar amino acidsnonpolar amino acids TyrPheLeuGlyAspLys

20. Biologically Active Peptides Vasopressin - Stimulates water reabsorption in the kidney Oxytocin - Stimulates lactation and uterine contraction Impact of changes in amino acids

21. Levels of Protein Structure

22. Forces Involved in Protein Structure

23. Primary Structure of Insulin

24. Primary Structure of Lysozyme

25.  -Helix Secondary Structure

26.  -Structure Secondary Structure

27. Collagen (triple helix)

28. Elastin Structure

29. Myoglobin: Secondary and Tertiary Structure  - helix

30. Myoglobin Surface View Cross-Section Heme Group

31. Lysozyme: Secondary and Tertiary Structure  - helix  - structure

32. Lysozyme: Tertiary Structure Active Site

33. Hemoglobin: Quaternary Structure Heme Group

34. Sickle-cell Hemoglobin valine-valine interaction

35. Electrophoresis of Hemoglobin A, Sickle-Cell Hemoglobin, and Hemoglobin C Hemoglobin S Glu to Val at Position 6 on the Beta Chain Hemoglobin C Glu to Lys at Position 6 on the Beta Chain

36. Protein Denaturation Denaturation involves The disruption of bonds in the secondary, tertiary and quaternary protein structures. Heat and organic compounds that break apart H bonds and disrupt hydrophobic interactions. Acids and bases that break H bonds between polar R groups and disrupt ionic bonds. Heavy metal ions that react with S-S bonds to form solids. Agitation such as whipping that stretches peptide chains until bonds break.

37. Applications of Denaturation  Use of silver nitrate solution in eyes of newborns to prevent gonorrhea infection  Use of eggs or milk as antidote for heavy metal poisoning  Use of tannic acid in burn ointment to coagulate proteins at burn site  Use of high temperature to sterilize items  Use of 70% ethanol or isopropyl alcohol as a disinfectant

38. Denaturation and Renaturation of Ribonuclease