Amino Acid Synthesis

Abstract

Green plants share with most microbial species the capacity to synthesize all the major amino acids; the few exceptions are parasitic and depend on the nitrogen metabolism of the host plant. In addition, many nonprotein “uncommon” amino acids are produced, and frequently accumulated, in large amounts in a range of species; these are important in plant/plant, plant/insect, and plant/animal relationships.¹ The amino acids essential for mammalian diets are phenylalanine, tryptophan, lysine, leucine, isoleucine, valine, threonine, and methionine for adults, with the addition of arginine and histidine for immature animals (the third aromatic amino acid required for protein synthesis, tyrosine, can be formed metabolically, given an adequate dietary intake of phenylalanine). The biosynthetic routes for these 10 amino acids are particularly attractive targets for toxicologically safe herbicides and for pesticides aimed at plant pathogens; the potential for antibiotics may be more limited because medicinally important microorganisms tend to inhabit nutritionally rich habitats.