1. CHMI 2227 - E.R. Gauthier, Ph.D. 1 CHMI 2227E Biochemistry I Peptides - General structure and properties

2. CHMI 2227 - E.R. Gauthier, Ph.D.2 Peptides 12 1 2 A dipeptide

3. CHMI 2227 - E.R. Gauthier, Ph.D.3 Peptides

4. CHMI 2227 - E.R. Gauthier, Ph.D.4 Peptides - polarity

5. CHMI 2227 - E.R. Gauthier, Ph.D.5 Peptides - nomenclature

6. CHMI 2227 - E.R. Gauthier, Ph.D.6 Peptide: hydrolysis

7. CHMI 2227 - E.R. Gauthier, Ph.D.7 High Pressure Liquid Chromatography (HPLC) PITC = phenylisothiocyanate PTC = phenylthiocarbamyl http://www.protein.iastate.edu/aaa.html

8. CHMI 2227 - E.R. Gauthier, Ph.D.8 High Pressure Liquid Chromatography (HPLC) http://www.protein.iastate.edu/aaa_figure3.html

9. CHMI 2227 - E.R. Gauthier, Ph.D.9 Peptide - ionization

10. CHMI 2227 - E.R. Gauthier, Ph.D.10 Example of peptides 1. Aspartame: artificial sweetener 2. Oxytocin: stimulates uterine contractions Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH 2 Glycinamide residue: 2 HN-CH 2 -CONH 2 SS Disulfide bond H 3 N + -CH-C-NH-CH-C-OCH 3 COO - CH 2 O O Asp-Phe-methyl ester

11. CHMI 2227 - E.R. Gauthier, Ph.D.11 Example of peptides 3.Insulin Intrachain disulfide bond Interchain disulfide bonds

12. CHMI 2227 - E.R. Gauthier, Ph.D.12 Example of peptides 4.Cystic Fibrosis Transductance Regulator

13. CHMI 2227 - E.R. Gauthier, Ph.D.13 General properties of proteins 1. Proteins differ in their Mr. Protein Mr (kDa) # residues # chains Insulin5.7512 Cytochrome c131041 Ribonuclease A13.71241 Lysozyme13.91291 Myoglobin16.91531 Chymotrypsin21.62413 Chymotrypsinogen222451 Hemoglobin64.55744 Serum albumin68.55501 Hexokinase1028002 Immunoglobulin G1451,3204 RNA polymerase4504,1005 Apolipoprotein B5134,5361 Glutamate dehydrogenase 1,0008,30040 Source: Biochemistry. Lehninger.

14. CHMI 2227 - E.R. Gauthier, Ph.D.14 Multimeric proteins Monomer/subunit Homodimer 1 1 Heterodimer 1 2 Hydrogen bonds: N-H ----- O-H N-H ----- N O-H ----- O=C N-H ----- O=C Hydrophobic interactions: -CH 3 CH 3 - CH 3 Electrostatic interactions: COO - ----- H 3 + N

15. CHMI 2227 - E.R. Gauthier, Ph.D.15 Importance of multimeric proteins – planar cell polarity

16. CHMI 2227 - E.R. Gauthier, Ph.D.16 Importance of multimeric proteins – planar cell polarity Nature Genetics 38, 21 - 23 (2006)

17. CHMI 2227 - E.R. Gauthier, Ph.D.17 General properties of proteins 2. Proteins differ in their pI. ProteinpI Pepsin1 Egg albumin4.6 Serum albumin4.9 Urease5  -lactoglobulin 5.2 Hemoglobin6.8 Myoglobin7 Chymotrypsinogen9.5 Cytochrome c10.7 Lysozyme11 Source: Biochemistry. Lehninger.

18. CHMI 2227 - E.R. Gauthier, Ph.D.18 General properties of proteins 3. Frequency of amino acid composition Number of residues per molecule of protein Amino Acid Human cytochrome c Bovine chymotrypsinogen Ala622 Arg24 Asn515 Asp38 Cys210 Gln210 Glu85 Gly1323 His32 Ile810 Number of residues per molecule of protein Amino Acid Human cytochrome c Bovine chymotrypsinogen Leu619 Lys1814 Met32 Phe36 Pro49 Ser228 Thr723 Trp18 Tyr54 Val323 Total104245

19. CHMI 2227 - E.R. Gauthier, Ph.D.19 General properties of proteins 3. Frequency of amino acid composition

20. CHMI 2227 - E.R. Gauthier, Ph.D.20 General properties of proteins 4. Proteins can include other chemical groups in addition to amino acids ClassProsthetic group Example LipoproteinLipids  1-lipoprotein (blood) Glycoprotein Carbohydrates (sugars) Immunoglobulin G (blood) Phosphoprotein Phosphate groups Casein (milk) Hemoprotein Heme (iron porphyrin) Hemoglobin Flavoprotein Flavin nucleotides Succinate dehydrogenase Metalloprotein Fe Zn Ca Cu Ferritin Alcohol dehydrogenase Calmodulin Plastocyanin

21. CHMI 2227 - E.R. Gauthier, Ph.D.21 General properties of proteins 5. Proteins have a specific shape Globular proteins Fibrillar (rod-like) proteins