Table 1.
First three principal components of amino acid physical properties.
| Amino acid | Principal Component 1 | Amino acid | Principal Component 2 | Amino acid | Principal Component 3 |
|---|---|---|---|---|---|
| K | -6.68 | W | -3.50 | C | -3.84 |
| R | -6.30 | R | -2.93 | H | -1.94 |
| D | -6.04 | Y | -2.06 | M | -1.46 |
| E | -5.70 | F | -1.53 | E | -1.46 |
| N | -4.35 | K | -1.32 | R | -0.91 |
| Q | -3.97 | H | -1.00 | V | -0.35 |
| S | -2.65 | Q | -0.47 | D | -0.18 |
| H | -2.55 | M | -0.43 | I | 0.04 |
| T | -1.42 | P | -0.36 | F | 0.05 |
| G | -0.76 | L | -0.20 | Q | 0.15 |
| P | -0.03 | D | 0.03 | W | 0.16 |
| A | 0.72 | N | 0.21 | N | 0.30 |
| C | 2.11 | I | 0.29 | Y | 0.37 |
| Y | 2.58 | E | 0.34 | T | 0.94 |
| M | 4.14 | T | 0.80 | K | 1.16 |
| V | 4.79 | S | 1.84 | L | 1.17 |
| W | 5.68 | V | 1.98 | G | 1.21 |
| L | 6.59 | A | 2.48 | S | 1.30 |
| I | 6.65 | C | 2.74 | A | 1.42 |
| F | 7.18 | G | 3.08 | P | 1.87 |
Principal component 1 is correlated with polarity or hydrophobicity, principal component 2 is correlated with size. The physical correlate of principal component 3 is not obvious but is generally considered to be electronic.