Synthesis Most of the amino acids that make up the protein are synthesized by Emden-Mayehof (Embden-meyerhof) pathway and the intermediate of citric acid circulation as carbon chain skeleton. The exception is aromatic amino acids, histidine, the former biosynthesis and the phosphoric acid in the middle of the red Moss sugar-phosphate, the latter is by ATP and phosphoric acid pyrophosphate synthesis. Microbes and plants synthesize all the amino acids in the body, and some of the amino acids in the animal are not synthesized in vivo (essential amino acids). Essential amino acids generally by the carbohydrate metabolism of the intermediate, the multi-step reaction (more than 6 steps) for the biosynthesis, the synthesis of non-essential amino acids requires about 14 enzymes, and the synthesis of essential amino acids need more, about 60 kinds of enzymes involved. Biosynthesis of amino acids, in addition to as a protein synthesis of raw materials, but also for the synthesis of alkaloids, lignin and so on. On the other hand, amino acids are decomposed in the organism as a result of amino-transfer or oxidation of ketones, or are decomposed as a result of the transformation of the carboxyl into amine.