DISSOCIATION OF THE AMINO GROUP (pKb) R C COONH2 H H + H NH3 + R C COO- + H + K2 = H NH2 R C COOR C COONH3 + H H + = K2 H NH2 R C COOR C COONH3 + H pH = pK2 Log H NH2 R C COOR C COONH3 + H [ ] [ ] +
DISSOCIATION OF THE AMINO GROUP (pKb) R C COONH2 H H + H NH3 + R C COO- + H + K2 = H NH2 R C COOR C COONH3 + H H + = K2 H NH2 R C COOR C COONH3 + H pH = pK2 Log H NH2 R C COOR C COONH3 + H [ ] [ ] +
[A-] pH = pK + Log [AH] [COO-] [NH2] pH - pK = Log or Log [COOH] [NH3+] RELATIONSHPI BETWEEN DISSOCIATION OF THE AMINO GROUP (pKb) AND pH
[A-] pH = pK + Log [AH] [COO-] [NH2] pH - pK = Log or Log [COOH] [NH3+] RELATIONSHPI BETWEEN DISSOCIATION OF THE AMINO GROUP (pKb) AND pH
pH 1 -1.2 -8.5 pH 2.2 0 -7.3 pH 3.5 1.3 -6 pH 5.5 3.3 -3.3 pH 7.5 5.3 -3 pH 9.5 7.3 0 pKa = 2.2 Log pKb = 9.5 Log pH 11.5 9.3 2 [COOH] [COO-] [NH3+] [NH2] Effects of pH on the Concentration of Different Groups
pH 1 -1.2 -8.5 pH 2.2 0 -7.3 pH 3.5 1.3 -6 pH 5.5 3.3 -3.3 pH 7.5 5.3 -3 pH 9.5 7.3 0 pKa = 2.2 Log pKb = 9.5 Log pH 11.5 9.3 2 [COOH] [COO-] [NH3+] [NH2] Effects of pH on the Concentration of Different Groups
pK' AND pI VALUES OF CERTAIN AMINO ACIDS pK'1 a - COOpK'2 a - NH3+ pK'R R Group pI Glycine 2.34 9.78 6.06 Alanine 2.35 9.69 6.02 Isoleucine 2.36 9.69 6.02 Serine 2.21 9.15 5.68 Aspartic Acid 2.09 9.82 3.86 2.97 Asparagine 2.02 8.80 5.41 Glutamic Acid 2.19 9.67 4.25 3.22 Glutamine 2.17 9.13 5.65 Histidine 1.82 9.17 6.00 7.58 Cysteine 1.71 10.78 8.33 5.02 Tyrosine 2.20 9.11 10.07 5.65 Arginine 2.17 9.04 12.48 10.76 Lysine 2.18 8.95 10.53 9.74
pK' AND pI VALUES OF CERTAIN AMINO ACIDS pK'1 a - COOpK'2 a - NH3+ pK'R R Group pI Glycine 2.34 9.78 6.06 Alanine 2.35 9.69 6.02 Isoleucine 2.36 9.69 6.02 Serine 2.21 9.15 5.68 Aspartic Acid 2.09 9.82 3.86 2.97 Asparagine 2.02 8.80 5.41 Glutamic Acid 2.19 9.67 4.25 3.22 Glutamine 2.17 9.13 5.65 Histidine 1.82 9.17 6.00 7.58 Cysteine 1.71 10.78 8.33 5.02 Tyrosine 2.20 9.11 10.07 5.65 Arginine 2.17 9.04 12.48 10.76 Lysine 2.18 8.95 10.53 9.74
GROUPS OF AMINO ACIDS 1. Aliphatic amino acids 2. Hydroxy amino acids 3. Acidic amino acids 4. Amide amino acids 5. Basic amino acids 6. Sulfur-containing amino acids 7. Aromatic amino acids 8. Secondary amino acids
GROUPS OF AMINO ACIDS 1. Aliphatic amino acids 2. Hydroxy amino acids 3. Acidic amino acids 4. Amide amino acids 5. Basic amino acids 6. Sulfur-containing amino acids 7. Aromatic amino acids 8. Secondary amino acids