Classification of amino acids
The amino acids according to the characteristics of the radical group, are divided by ionization, polarity and reactivity, in:
- Neutral amino acids. Its side chain does not have carboxyl or amino groups and, therefore, at neutral pH its net electric charge is 0. They can be:
- Polar neutrals. Its side chain has hydrophilic groups with which it can form hydrogen bonds with polar molecules, making it soluble in water.
- Nonpolar neutrals. Its long side hydrocarbon chain is hydrophobic, and it is less soluble in water.
- Acidic amino acids: the R group carries an acid group (carboxyl), so that at neutral pH, they have a negative charge, since that group releases H+.
- Basic amino acids: when the R group carries a basic group (amino), in such a way that at neutral pH, they have a positive electrical charge (take H+).