Amino Acid Biosynthetic Families, Grouped by Metabolic Precursor a-Ketoglutarate Pyruvate Glutamate Alanine Glutamine Valine Proline Leucine Arginine" Phosphoenolpyruvate and 3-Phosphoglycerate erythrose 4-phosphate Serine tryptophan Glycine Phenylalanine Cysteine Tyrosine Oxaloacetate Ribose 5-phosphate Aspartate Histidine Asparagine Methionine Threonine Lysine Isoleucine Essential in young animals T Essential amino acids 'Derived from phenylalanine in mammals.氨 基 酸 合 成 家 族 ： 合 成 前 体 分 类