Amino Acids The Building Blocks of Protein carry out various biological functions capacity to polymerize protein linear heteropolymers of a amino acids useful acid base properties varied physical properties Varied chemical functionality as as as a i a im Tano as peptides Protein AMINO acids Share many features only differing at the R substituent group Three common functional groups attached to the a carbon a carbon always has four substituents and is tetrahedral MAGI 1pA mg fM y All amino acids except proline have an acidic carboxyl group connected to the a carbon a basic amino group connected to the a carbon an A hydrogen connected to the a carbon The fourth substituent R group is unique Exception Glycine the simplest amino acid R group IS hydrogen H H E X f 2N O Glycine Ely E MIN 75 07 CH I H cooH Alanine Ala A MIN 89 09 j OH serine Caseros man OH I HzN C00H Threonine Cthr 1 MW 119 lipka 16 s t HzN H Methionine CME 1 14 NIKI 149 2 1 Y 1 1 14 001 1 Isoleucine 11 1 MIN 131 2 H 7 1 t H N cooH Tryptophan lTrp IN MW 204 2 go s O OH HN 10001 1 Aspartic Acid ASRD 2 MIN 133 1 PKa 3 9 SH HZN COOH cysteine ccyssc MIN 21 2 pka 8 18 it H COOH Proline Pro P MIN 115 1 OH I HzN cooH Glutamic Acid Glu E 141 1 147 1 pKa 4 07 0 MHz MHz COOH H N Asparagine Asn N MW 132 1 I 1 1 14 1 COOH Glutamine G In Q MIN 146 1 HNA 1111 1 0 a o I H nl 1cooH Histidine H s MIN 55 2 pKa 6 04 NH I I a HZN COOH Lysine Lys k MIN 46 2sPKa 0 79 NH HZN NHz COOH HZN Arginine Arg R MIN L 4 2 pKa 12 48 Classifications and properties determined by Three Letter Code One Letter Code it I COOH HZN Hahne at MW 117 1 f f t A COOH I COOH HZN Leucine Leu L MW 1311 2 a I l 1 1 111 0001 1 Tyrosine Tyr Y MIN 181 2 pKa 10 46 HZN Phenylalanine Phe F MW 165 2 so 6 to gg I o E o o E R Substituents Nonpolar aliphatic 7 Aromatic 3 Polar uncharged 5 Positively charged 3 Negatively charged 2 Amino Acid Alanine Arginine Aspartic Acid Asparagine Cysteine Glutamic Acid Glutamine Glycine Histidine Isoleucine Leucine Lysine Methionine phenylalanine Proline Serine Threonine Tryptophan Tyrosine Valine Ala Arg Asp Ash Cys Glu Gin Gly HIS Ile Leu Lys Me 1 Phe Pro Ser Thr Trp Tyr Val A R D N C E Q G H L K M F P S T IN Y V Nonpolar Amino Acids Nonpolar aliphatic R groups HzN C H I H Glycine Cfo HzN C H th COO 4 1 1 Hani ICH Hac Ctia Alanine proline COO 1 3N C H 1 3 Valine N c H H N g H H C CH COO I I 2 CH COO CH I 4 12 5 CH COO I H H CH 1 CH CH Leucine CH Isoleucine Methionine Full Name Three Letter Code One Letter Code Glycine Alanine proline Valine Leucine Isoleucine Methionine City Ala Pro Val Leu Ile Met G A P P L 1 M Aromatic R groups HN 3 C H COO 1 CH I Phenylalanine COO H N C H I CHZ it I OH Tyrosine H N COO C H 2 1 C CH Tryptophan NH Aromatic Amino Acids Three Letter Code One Letter code Full Name phenylalanine Tyrosine Tryptophan pine Tyr Trp P y w Polar Uncharged Amino Acids Polar uncharged R groups COO HN C H I CHZOH Serine COO H N C H H C OH I CH Threonine HzN C H COO I I CH 1 SH cysteine COO y H N C H 1 CHZ I C to HZN Asparagine H N C H COO I 4 2 CHZ 1 C No HZN Glutamine Full Name Three Letter Code One Letter code serine Threonine Cysteine Asparagine Glutamine Ser Thr Cys Asn G In 5 T C N Q Positive Charged Amino Acids Positively Charged R groups Three Letter Code One Letter code Full Name Lysine Arginine Histidine Lys Arg His K R H COO HZN C H Ctlz CH z 1 CHZ I CY NH Lysine e HN C H CHZ I 4 12 NH 1 C NHz I NHZ Arginine COO H N d H 4 2 1 C NH CH C N H Histidine Negative Charged Amino Acids Negatively Charged R groups COO I Hz g H CH z COO Aspartate COO 1 HzN C H CHZ I COO Glutamate Full Name Aspartate or Aspartic Acid Glutamate Cor Glutamic Acid Three Letter Code One Letter code ASP 1 E Modified Amino Acids Fountain Proteins OH Coo N Hz 4 Hydroxyproline Hz CH CY CHZ CH OH CY Coo NH 5 Hydroxylysine CH NH CH CH CH CH CH COO 6 N Methyllysine l NH 3 HzN 00C ICH ICH z H ICH z CH COO HzN cool 4 1 3 N Ktla I CH I Coo Desmosine Hse CH CH COO I NH Selenooysteine COON 00C Cti CH CH Coo I NH 4 Carboxyglutamate 1 C NH CH CH CH CH CH COO CH I NH Pyrrolysine Reversible Modifications Of Amino Acids O p O CH CH COO I NH Phosphoserine 41 13 O P O CH CH coolI NH 0 Phosphothreonine 0 I O 0 11 CHZ CH Coo NH O p o 1 0 Phosphotyroslne HIN HN I CH NH CHz CHz CHz c tl COO NH W N Methyl arginine HN CH CH CH CHZ CH COO I NH l C o I CH 6 N Acetyllysine 0 Hgc O Y CH CH GH COO NH Glutamate g methyl ester MHz I AN 1 Y N N i P o E to c coi I NH OH OH Adenylyltyrosine Amino Acids Polymerize 10 form peptides Peptides are small condensation products of amino acids small compared to proteins M 10 kDa 43N R H R2 DH c OH 11 1 N DH cook H2O H2O R I H Rz H N CH C IN ait Coo Peptide Nomenclature AA AAZ AA AAS Numbering and naming starts from the amino terminus N terminal AA OH CH CH 4 1 H 41 12 4 13 H2 HzN C C N C c N C C N C C N c cool ti ti o 41 1201 1 Y 11 I H O 11 1 H 0 Using full amino acid names serylglycyltyrosylalany leucine using three letter code abbreviation Ser Gly Tyr ala Leu Carboxyl terminal end 10h90 Peptides lllkep ro e1ns one1e ercode SEYAL Amino terminal end N terminal C terminal