Of these, β-alanine is found in mammals and incorporated in pantothenic acid, an essential nutrient. Two α-amino acids are also structurally β-amino acids: aspartic acid and asparagine. Microcystins are a class of compounds containing a β-isoaspartyl (i.e. aspartic acid linked with its beta-carboxyl) residue. See also Peptidomimetic References Peptides