Organic Chemistry,5th Edition L.G.Wade,Jr. Chapter 24 Amino Acids. Peptides,and Proteins Jo Blackburn Richland College,Dallas,TX Dallas County Community College District ©2003，Prentice Hall
Chapter 24 Amino Acids, Peptides, and Proteins Jo Blackburn Richland College, Dallas, TX Dallas County Community College District © 2003, Prentice Hall Organic Chemistry, 5th 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 => 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 一OH a-amino group R -side chain an d-amino acid peptide bonds 3-NH-CH-C-NH-CH一C∠NH一CH-C-NH-CH一C-NH-CH一( CH3 CH2OH H CH>SH CH(CH3)2 a short section of a protein H2N-CH-C-OH H2N-CH-C OHHN一CH一C OHHN一CH- C- OH H2N-CH- OH CH3 CHOH H CH2SH CH(CH3)2 alanine serine glycine cysteine valine individual amino acids 三> 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 H CCH-OH H COOH CHO COOH H2N- -H HO H H2N- H CH3 CH,OH R (S)-alanine L-(-)-glyceraldehyde an L-amino acid (L-alanine) (S)configuration => Chapter 24 5
Chapter 24 5 Stereochemistry of -Amino Acids =>