D-tryptophan  is the D-form (non-proteinogenic form) of the amino acid tryptophan. It can be used for Human embryonic kidney cell (HEK-293, ATCC: CRL-1573) culture. It is also a sweetener used to study the release of incretins from enteroendocrine cells triggered by sugar but not by sweeteners.

D-tryptophan  (Full name D (+)-Tryptophan) is a white to pale yellow or white crystalline powder at room temperature, odorless or slight odor, slightly sweet taste. Solubility in water is 1.14 g (25 ºC), soluble in dilute acid and alkali, stable in alkali, decomposed in strong acid, slightly soluble in ethanol, not soluble in chloroform, ethyl ether. It plays an important role for human and animal growth and development, metabolism, known as the second essential amino acids. They are almost identical with L-type and physical and chemical properties, and only the optical activity is opposite. But their distribution, function and coenzyme have diversity. Its melting point is very high, generally above 200 degrees. It can dissolve in water, and in the near UV region it has the ability to absorb light.

Function
1. Keep the balance of amino acids in the forage and stimulate the growth of the animals;
2. Improve the meat quality;
3. Increase the nutritive value of forage raw materials which have low amino acid digestibility;
4. Apply to the production low-protein forage;
5. Cut down the cost of raw materials for forage;
6. Decrease the nitrogen content in the excrement and urine of animals so that the release of ammonia is slowed and the ammonia concentration is kept low in animal shed.

Application

1.Used in biochemical studies, and in medicine as a sedative. 
2.Used as Amino acids. Often combined with iron, vitamins and others,and can improve depression when compined with VB6 , rough skin disease of prevention and cure; 
3.Used as a sedative for insomnia with L-dopa for the treatment of Parkinson's disease. The carcinogenicity of experimental animal; nausea, anorexia, wheezing and other adverse reactions to sleep. Avoid combined with monoamine oxidase inhibitors.