1、Charpter 1 Amino acids1. Objective and requirement(1) After learning this chapter, students should have a good mastery of the key conception of AAs; the general structure & classification of AAs; AAs with nonpolar side chain and its location in proteins; AAs with uncharged polar side chains; AAs

2、 with acidic and basic side chains; amphoteric dissociation & pI of AAs.(2) After learning this chapter, students should have a fair knowledge of abbreviations and symbols for commonly occurring AAs; optical properties of AAs;(3)After learning this chapter, students should have some acquaintance

3、 with Henderson-Hasselbalch equation and its application.2. Major teaching contents . OVERVIEW. STRUCTURE OF THE AMINO ACIDS. ACIDIC & BASIC PROPERTIES OF AAs. CONCEPT MAPS. CHAPTER SUMMARY3. Important points(1) Basic Structure and classification of amino acids (2) Acids, bases ,pH and ionizatio

4、n of amino acids 4.Difficult points(1)Stereoisomers of amino acids (2) Henderson-Hasselbalch equation and its application5. Teaching method: Heuristic6. Teaching aid: Multimedia Courseware7.Teacher : Zeng Wei Min8.Students: the Grade 2010 students majoring in biological science 9. Classroom: T111 cl

5、assroom 10. Textbook Lippincott's Illustrated Reviews: Biochemistry (5th edition) by Pamela C. Champe, 2011年出版 11. Reference 1.生物化學(xué)王鏡巖主編 第三版，北京：人民衛(wèi)生出版社，20022. 生物化學(xué) 周愛儒等主編 第七版 北京 人民衛(wèi)生出版社，20083. Instant Notes in Biochemistry B.D.Hames,N.M.Hooper and J.D.Houghton. Bios Scientific Publishers Limited

6、,1997 4. Medical Biochemistry (Second Edition),Alexander C. Brownie & John C. Kernohan, 2005Chapter 1 Amino acids. OVERVIEW1. Proteins are the most abundant & functionally diverse macromolecules in living systems. 2. The composition of AAs in protein related to the structure and function of

7、protein. . STRUCTURE OF THE AMINO ACIDSStereoisomerUn-ionized formzwitterion General structure-A. Amino acids with nonpolar side chains1. 9 AAs in total: Gly(G), Ala(A), Val(V), Leu(L), Ile(I), Phe(F), Trp(W), Met (M), Pro(P)2. Their R groups cant bind or give off H+ or participate in H- or ionic bo

8、nds 3. They can promote hydrophobic interactions.-A-1. Location of nonpolar AAs in proteins -A-2. Proline -B. AAs with uncharged polar side chains1. There are 6 AAs in total: Ser(S), Thr(T), Tyr(Y), Asn(N), Gln(Q), Cys(C)2. Their R-groups have zero net charge at neutral pH. 3. The side chains of Cys

9、 & Tyr have negative charge at alkaline pH. 4. Ser, Thr and Tyr contain a polar hydroxyl group (H-bonds, phosphorylation)5. Asn & Gln contain a carbonyl group & an amide group (H-bonds),Cys contains SH(-S-S-).-B-1. Disulfide bond-B-2. Side chains as sites of attachment for other compound

10、s-C. Amino acids with acidic side chains -D. Amino acids with basic side chains-E. Abbreviations & symbols for commonly occurring AAs-F. Optical properties of amino acids . ACIDIC & BASIC PROPERTIES OF AAs pH pKa + log A-/HA-A. Derivation of the equation-B. Buffer1. A buffer solution is a so

11、lution able to absorb a certain quantity of acid or base without undergoing a strong variation in pH. There is at least an acid-base conjugate pair in buffer solution.2. Maximum buffering capacity occurs at a pH equal to the pKa, The effective buffering region is within approximately ±1 pH unit of the pKa.-C. Titration of an amino acid -C-1. Dissociation of the carboxyl group-C-2. Application of the H-H equation -C-3. Dissociation of the amino group-C-4. pKs of the alanine-C-5. Titration curve of the alanine-C-6. Net charge of AAs at neutral pH -