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