单语范例（未经PONS编辑处理）
The fourth aromatic amino acid tyrosine can be synthesized from phenylalanine.
en.wikipedia.org It contains hydrophilic amino acid residues aligned along one side and hydrophobic amino acid residues aligned along the opposite side of a helical molecule.
en.wikipedia.org Peptide chains in crustaceans are about 660 amino acid residues long, and in chelicerates they are about 625.
en.wikipedia.org Protein consumption has shown to be beneficial for bone density by providing amino acid substrates necessary for bone matrix formation.
en.wikipedia.org The less well conserved the enzyme is, the more amino acid differences will be present in even closely related species.
en.wikipedia.org