It is important to note that there are approximately 500 amino acids, but proteins in the human body are mostly comprised of 20 amino acids, which can be further categorized into three main groups. There are essential amino acids, nonessential amino acids, and conditional amino acids. The former group includes valine, tryptophan, threonine, phenylalanine, methionine, lysine, leucine, isoleucine, and histidine (“Amino acids reference charts”). The nonessential group involves tyrosine, serine, proline, glycine, glutamine, glutamic acid, cysteine, aspartic acid, asparagine, arginine, and alanine (“Amino acids reference charts”). The essential amino acids are the ones, which cannot be produced within the body, which is why they need to be consumed through food, whereas nonessential ones can be produced from other amino acids (“Amino acids reference charts”). In addition, depending on a condition, such as stress or illness, some nonessential amino acids can become essential due to certain factors, which makes them conditional amino acids, and they include serine, proline, ornithine, glycine, tyrosine, glutamine, cysteine, and arginine.
Alanine is an amino acid abbreviated either as Ala or A, and the radical group is comprised of CH3. It can be categorized as an aliphatic amino acid, which means that its side chain is hydrophobic (“Amino acids reference charts”). Phenylalanine is an amino acid abbreviated as Phe or F, where the side chain is also hydrophobic, but it is not a methyl group but rather an aromatic ring (“Amino acids reference charts”). Cysteine is abbreviated as Cys or C, and it contains the radical group with a sulfur atom (“Amino acids reference charts”). It is important to note the fact that cysteine’s side chain is a polar neutral one, which means that it is neither acidic nor basic.
Reference
“Amino acids reference charts.” Merck, 2021. Web.