ASCII Drawings and Symbols of the 20 Amino Acids NONPOLAR ALIPHATIC R groups (Glycine G, Alanine A, Leucine L, Valine V Isoleucine I, Proline P) Glycine Gly G C00- + | H3N---C-H | H Alanine Ala A COO- + | H3N---C-H | CH3 Valine Val V COO- + | H3N---C-H | CH / \ CH3 CH3 Leucine Leu L COO- + | H3N---C-H | CH2 | CH2 / \ CH3 CH3 Isoleucine Ile I COO- + | H3N---C-H | CH | C--CH2 | CH2 | CH2 Proline Pro P COO- + | H2N---C---H | \ | \ | CH2 | | H2C-------CH2 ====================================================== POLAR UNCHARGED (Serine S, Threonine T, Cysteine C, Asparagine D, Methionine M, Glutamine E) Serine Ser S COO- + | H3N---C-H | CH2OH Threonine Thr T COO- + | H3N---C-H | HCOH | CH3 Cysteine Cys C COO- + | H3N---C-H | H2CSH Methionine Met M COO- + | H3N---C-H | CH2 | CH2 | S | CH3 Asparigine Asn D COO- + | H3N----C-H | CH2 | H2N-C=O <== amide group Glutamine Glu E COO- + | H3N---C-H | CH2 | CH2 | H2N-C=O <--amide group ======================================= AROMATIC R GROUPS (Phenylalanine F, Tyrosine Y, Tryptophan W) Phenylalanine Phe F COO- + | H3N----C-H | CH3 | // \ // \ | || | || \\ / \\ / tYrosine Tyr Y COO- + | H3N---C-H | CH3 | // \ // \ | || | || \\ / \\/ | OH Tryptophan Trp W COO- + | H3N---C-H | C==C+ (???) | \ | \ | NH | / C======/ / \ / \ || | || | \ // \ // \ // ====================== POSITIVELY CHARGED R (Lys K, Arg R, His H) Lysine Lys K COO- + | H3N----C-H | CH2 | CH2 | CH2 | CH2 | + NH3 Arginine Arg R COO- + | H3N----C-H | CH2 | CH2 | CH2 | NH | + C==NH2 | NH Histidine His H COO- + | H3N---C-H | C---NH || \ || \ || CH2 || // C--------N ======================================= Negatively Charged R (Aspartate Asp D, Glutamate Glu E) Aspartate Asp D COO- + | H3N---C-H | CH2 | COO- Glutamate Glu E COO- + | H3N---C-H | CH2 | CH2 | COO- (this is where the Na goes in MSG)