| Amino Acid | 1-Letter | 3-Letter | MW (Da) | pKa (Ξ±-COOH) | pKa (Ξ±-NHβ) | pI | Hydrophobicity | Group |
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How to Use the Amino Acid Properties Table
Search: Type an amino acid name (e.g. Alanine), three-letter code (e.g. Ala), or one-letter code (e.g. A) to filter the table instantly.
Filter by group: Use the filter buttons to show only nonpolar, polar, charged, or aromatic amino acids.
Detailed view: Click any row in the table to expand a full detail panel with all properties, side chain pKa, and chemical group description.
About Amino Acid Properties
The 20 standard amino acids differ in the chemical nature of their side chains (R groups), which determines their physical and chemical properties. These properties govern protein structure, folding, and function.
MW (Da): Residue molecular weight (minus water for peptide bonds)
pKa (Ξ±-COOH): Ionization of alpha-carboxyl group (~2.0β2.4)
pKa (Ξ±-NHβ): Ionization of alpha-amino group (~9.0β10.8)
pI: Isoelectric point β pH at net charge = 0
Hydrophobicity: Kyte-Doolittle scale (β4.5 to +4.5)
// Positive = hydrophobic, Negative = hydrophilic
Chemical Groups
Amino acids are classified into groups based on side chain polarity and charge at physiological pH (7.4): nonpolar aliphatic, aromatic, polar uncharged, negatively charged (acidic), positively charged (basic), and special cases (Glycine, Cysteine, Proline).