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p.1127 Chapter 22 Amino Acids, Peptides, and Proteins

p.1128

p.1128 Amino acid Peptide

Amino acid

p.1132

p.1128

p.1129

p.1130

p.1131

pk a

pka's of Inorganic and Oxo-Acids Chem 206 Substrate pka H 2 O (DMSO) Substrate pka H 2 O(DMSO) Substrate pka H 2 O (DMSO) Substrate pka H 2 O (DMSO) INORGANIC ACIDS CARBOXYLIC ACIDS ALCOHOLS PROTONATED SPECIES H 2 O H 3 O + H 2 S HBr HCl HF HOCl HClO 4 HCN HN 3 HSCN H 2 SO 3 H 2 SO 4 H 3 PO 4 HNO 3 HNO 2 H 2 CrO 4 CH 3 SO 3 H CF 3 SO 3 H NH 4 Cl B(OH) 3 HOOH 15.7 (32) -1.7 7.00-9.00 (0.9) -8.0 (1.8) 3.17 (15) 7.5-10 9.4 (12.9) 4.72 (7.9) 4.00 1.9, 7.21-3.0, 1.99 2.12, 7.21, 12.32-1.3 3.29-0.98, 6.50-2.6 (1.6) -14 (0.3) 9.24 9.23 11.6 X X= CH 3 CH 2 NO 2 CH 2 F CH 2 Cl CH 2 Br R O OH CH 2 I CHCl 2 CCl 3 CF 3 H HO C 6 H 5 o-o 2 NC 6 H 4 m-o 2 NC 6 H 4 p-o 2 NC 6 H 4 o-clc 6 H 4 m-clc 6 H 4 R= H trans-co 2 H cis-co 2 H 4.76 (12.3) 1.68 2.66 2.86 2.86 p-clc 6 H 4 3.99 o-(ch 3 ) 3 N + C 6 H 4 1.37 p-(ch 3 ) 3 N + C 6 H 4 3.43 p-omec 6 H 4 O OH 3.12 1.29 0.65-0.25 3.77 3.6, 10.3 4.2 (11.1) 2.17 2.45 3.44 2.94 3.83 4.47 4.25 3.02, 4.38 1.92, 6.23 HOH MeOH i-proh t-buoh m-o 2 NC 6 H 4 OH p-o 2 NC 6 H 4 OH p-omec 6 H 4 OH 15.7 15.5 16.5 17.0 c-hex 3 COH 24.0 CF 3 CH 2 OH (CF 3 ) 2 CHOH C 6 H 5 OH 12.5 8.4 7.1 10.2 PEROXIDES 11.5 8.2 (31.2) (27.9) (29.3) (29.4) (23.5) (18.2) 9.95 (18.0) (10.8) (19.1) 2-napthol (17.1) OXIMES & HYDROXAMIC ACIDS Ph Ph Ph N O O OH Ph N H N Me MeOOH CH 3 CO 3 H OH OH 9.3 11.3 (20.1) 8.88 (NH) (13.7) (18.5) Ph Ph + + O N + OH OH OH OH Ph CH 3 H O + Ph Me H Me O+ Me H H O + Me H + OH O + S Me Me Me OH Me N OH N + Me -12.4-7.8-6.2-6.5-3.8-2.05-2.2-1.8 0.79 (+1.63) (+5.55) SULFINIC & SULFONIC ACIDS O O Me S OH O Ph S OH -2.6 2.1 pka Table.1 11/4/05 1:43 PM *Values <0 for H 2 O and DMSO, and values >14 for water and >35 for DMSO were extrapolated using various methods. For a comprehensive compilation of Bordwell pka data see: http://www.chem.wisc.edu/areas/reich/pkatable/index.htm

Substrate pka H 2 O (DMSO) INORGANIC ACIDS H 2 O 15.7 (32) H 3 O + -1.7 H 2 S 7.00 HBr -9.00 (0.9) HCl -8.0 (1.8) HF 3.17 (15) HOCl 7.5 HClO 4-10 Substrate pka H 2 O (DMSO) HOH MeOH i-proh t-buoh ALCOHOLS 15.7 15.5 16.5 17.0 (31.2) (27.9) (29.3) (29.4) c-hex 3 COH 24.0 CF 3 CH 2 OH (CF 3 ) 2 CHOH 12.5 9.3 (23.5) (18.2) C 6 H 5 OH 9.95 (18.0) HCN HN 3 HSCN 9.4 4.72 4.00 (12.9) (7.9) H 2 SO 3 H 2 SO 4 1.9, 7.21-3.0, 1.99

pk a CH 3 COOH ClCH 2 COOH ClCH 2 CH 2 COOH ClCH 2 CH 2 CH 2 COOH ClCH 2 CH 2 CH 2 CH 2 COOH Cl 2 CHCOOH Cl 3 CCOOH FCH 2 COOH pk a 4.8 2.8 4.1 4.5 4.7 1.3 0.7 2.6 Cl CH 2 C O O " Delocalization of N by Inductive Effect

p.13

Amino Acid α- α-nh 2 Side chain p.1136 Alanine 2.35 9.87 Arginine 2.01 9.04 12.48 Asparagine 2.02 8.80 Aspartic Acid 2.10 9.82 3.86 Cysteine 2.05 10.25 8.00 Glutamic Acid 2.10 9.47 4.07 Glutamine 2.17 9.13 Glycine 2.35 9.78 Histidine 1.77 9.18 6.10 Isoleucine 2.32 9.76 Leucine 2.33 9.74 Lysine 2.18 8.95 10.53 Methionine 2.28 9.21 Phenylalanine 2.58 9.24 Proline 2.00 10.60 Serine 2.21 9.15 Threonine 2.09 9.10 Tryptophan 2.38 9.39 Tyrosine 2.20 9.11 10.07 Valine 2.29 9.72

Amino Acid α- α-nh 2 Side chain p.1128 Glycine 2.35 pk a1 = 2.35 9.78 pk a2 = 9.78 COOH COO - + H + NH 3+ NH 2 + H +

Amino Acid α- α-nh 2 Side chain p.1130 Alanine 2.35 9.87 Aspartic Acid 2.10 9.82 3.86 COOH COO - + H + COOH COO - + H + NH 3+ NH 2 + H +

Amino Acid α- α-nh 2 Side chain p.1130 Aspartic Acid 2.10 9.82 3.86 Glutamic Acid 2.10 9.47 4.07 COOH COO - + H + COOH COO - + H + NH 3+ NH 2 + H +

Amino Acid α- α-nh 2 Side chain p.1130 Glutamic Acid 2.10 9.47 4.07 Glutamine 2.17 9.13

Amino Acid α- α-nh 2 Side chain p.1130 Glutamic Acid 2.10 9.47 4.07 Lysine 2.18 8.95 10.53 COOH COO - + H + NH 3+ NH 2 + H + NH 3+ NH 2 + H +

Amino Acid α- α-nh 2 Side chain p.1131 Lysine 2.18 8.95 10.53 Histidine 1.77 9.18 6.10

Amino Acid α- α-nh 2 Side chain p.1131 Phenylalanine 2.58 9.24 Tyrosine 2.20 9.11 10.07

pi Isoelectric point

p.1138

pk 1 =1.77, pk 2 =6.10, pk 3 =9.18 p.1137

p.1139

p.1140

p.1143

p.1148

p.1153

p.1148

p.1149

p.1150

p.1151

p.1152

p.1154

http://www.ks.uiuc.edu/research/smd_imd/pla2/

p.1155

p.1153

Dr. Robert Bruce Merrifield, 1984

p.1157

L-Asp + L-Phe Asp-Phe L-Asp-L-Asp L-Asp-L-Phe L-Phe-L-Asp L-Phe-L-Phe

DL-Asp + DL-Phe Asp-Phe L-Asp-L-Asp L-Asp-L-Phe L-Phe-L-Asp L-Phe-L-Phe D-Asp-D-Asp D-Asp-D-Phe D-Phe-D-Asp D-Phe-D-Phe L-Asp-D-Asp L-Asp-D-Phe L-Phe-D-Asp L-Phe-D-Phe D-Asp-L-Asp D-Asp-L-Phe D-Phe-L-Asp D-Phe-L-Phe

L-Asp-L-Asp L-Asp-L-Phe L-Phe-L-Asp L-Phe-L-Phe L-Asp-D-Asp L-Asp-D-Phe L-Phe-D-Asp L-Phe-D-Phe D-Asp-D-Asp D-Asp-D-Phe D-Phe-D-Asp D-Phe-D-Phe D-Asp-L-Asp D-Asp-L-Phe D-Phe-L-Asp D-Phe-L-Phe

p.1169