Organic Chemistry,6th Edition L.G.Wade,Jr. Chapter 24 Amino Acids. Peptides,and Proteins Jo Blackburn Richland College,Dallas,TX Dallas County Community College District ©2006，Prentice Hall
Chapter 24 Amino Acids, Peptides, and Proteins Jo Blackburn Richland College, Dallas, TX Dallas County Community College District © 2006, Prentice Hall Organic Chemistry, 6th Edition L. G. Wade, Jr
Proteins Biopolymers of a-amino acids. Amino acids are joined by peptide bond. Variety of functions: >structure >enzymes >transport >protection >hormones 二> Chapter 24 2
Chapter 24 2 Proteins • Biopolymers of -amino acids. • Amino acids are joined by peptide bond. • Variety of functions: ➢structure ➢enzymes ➢transport ➢protection ➢hormones =>
Structure of Proteins a carbon atom H.N-CH-C-OH a-amino group R -side chain an a-amino acid H2N-CH-C-OH H2N-CH-C-OH HN-CH- OH HN-CH-C-OHHN-CH-C-OH CH,OH H CH2SH CH(CH3)2 alanine serine glycine cysteine valine several individual amino acids peptide bonds -NH-CH一C-NH- CH-CNHCH- NH-CH- NH- CH- CH3 CHOH H CH,SH CH(CH3) a short section of a protein Copyright2005 Pearson Prentice Hall,Inc. Chapter 24 3
Chapter 24 3 Structure of Proteins =>
Amino Acids .-NH2 on the carbon next to -COOH. Glycine,NH2-CH2-COOH,is simplest. With-R side chain,molecule is chiral. Most natural amino acids are L-amino acids,related to L-(-)-glyceraldehyde. Direction of optical rotation,(+)or () must be determined experimentally. > Chapter 24
Chapter 24 4 Amino Acids • -NH2 on the carbon next to -COOH. • Glycine, NH2 -CH2 -COOH, is simplest. • With -R side chain, molecule is chiral. • Most natural amino acids are L-amino acids, related to L-(-)-glyceraldehyde. • Direction of optical rotation, (+) or (-), must be determined experimentally. =>
Stereochemistry of a-Amino Acids COOH CHO COOH HO C R H H COOH CHO COOH H HO H H2N H CH3 CH2OH R L-alanine L-(-)-glyceraldehyde an L-amino acid (S)-alanine (S)-glyceraldehyde (S)configuration Copyright2005 Pearson Prentice Hall,Inc. => Chapter 24 5
Chapter 24 5 Stereochemistry of -Amino Acids =>