What are standard amino acids?
The 20 standard amino acids are “proteinogenic” meaning they are naturally genetically encoded and can be incorporated into proteins during translation. Each amino acid carries a unique R group that renders it with specific chemical properties. In turn, the amino acids in a peptide sequence dictate the peptide properties such as hydrophobicity, solubility, and charge. L amino acids are the natural form (designated by upper case letters), and D amino acids are the unnatural form (designated by lower case letters).