Linked from
The 9 pages that link to Proteinogenic amino acid, each with the reason it gives.
Essential amino acidRelated: Most essential amino acids are needed to make proteins.
GlycineNarrower topic: Glycine is one of the standard residues encoded by the genetic code.
SerineNarrower topic: Serine is directly encoded in the genetic code and incorporated into proteins.
ArginineNarrower topic: Arginine is one of the standard amino acids used to build proteins.
HistidineNarrower topic: Histidine is one of the 20 standard protein-building amino acids.
AlanineNarrower topic: Alanine is encoded by the genetic code and incorporated into proteins.
ValineNarrower topic: Valine is one of the standard amino acids used during protein synthesis.