Amino Acids: Complete Guide
Glycine, Alanine, Valine, Leucine, Isoleucine, Proline, Methionine, Phenylalanine, and Tryptophan are nonpolar and hydrophobic. Nonpolar means that the electrical charges on the molecule are evenly distributed, resulting in no “poles” that are negative or positively charged. Hydrophobic means that it repels water. Out of these 9 amino acids, Phenylalanine and Tryptophan are aromatic, meaning that their structure is ring-shaped, which results in increased stability. Use the mnemonic “GAVLIP” paired with “MetPheTrp” to memorize them!
Nonpolar/Hydrophobic: GAVLIP, MetPheTrp
Glycine, Alanine, Valine, Leucine, Isoleucine, Proline, Methionine
Phenylalanine (aromatic), Tryptophan (aromatic)
Serine, Cysteine, Threonine, Asparagine, Glutamine, and Tyrosine are the polar, hydrophilic, and uncharged amino acids. Polar means that the electrical charges on the molecules are not evenly distributed, resulting in “poles” of negative or positive charge. They are hydrophilic, meaning water-loving. They are also uncharged, meaning they have equal numbers of electrons (negative) and protons (positive). Tyrosine is aromatic. Use the mnemonic “SCTAG” paired with “Tyrosine” to memorize them!
Polar/Hydrophilic Uncharged: SCTAG, Tyrosine
Serine, Cysteine, Threonine, Asparagine, Glutamine
Tyrosine (aromatic)
Aspartic Acid, Glutamic Acid, Lysine, Arginine, and Histidine are the polar, hydrophilic, and charged amino acids. Charged means that they have unequal numbers of electrons and protons. Out of these five, the amino acids with an acid in their name, Aspartic Acid and Glutamic Acid, are negatively charged, meaning they have more electrons. Lysine, Arginine, and Histidine are Tyrosine (aromatic), meaning they have more protons. Note: the exact charge of an amino acid (whether negative, neutral, or positive) depends on the environmental pH These charges are based on an environment at physiological pH, which is ~7.4 pH.
Polar/Hydrophilic Charged:AGLAH,
Aspartic Acid (-), Glutamic Acid (-), Lysine (+), Arginine (+), Histidine (+)
