D-tryptophan is a white or off-white to slightly yellowish crystalline powder at room temperature, odorless or slightly odorous, and has a slightly sweet taste.  It has a solubility of 1.14 grams in water (at 25℃), dissolves in dilute acids and dilute bases, is stable in bases, and decomposes in strong acids. It is slightly soluble in ethanol and insoluble in chloroform and ether. It plays an important role in the growth, development and metabolism of humans and animals and is known as the second essential amino acid.  It can be used as a non-nutritive sweetener, feed additive and plant growth agent in the food and feed industry as well as agriculture . In the pharmaceutical industry, it is mainly used to synthesize various polypeptides, replacing L-tryptophan to extend the half-life of peptide drugs and reduce side effects, without causing drug resistance, and thus has become an important precursor for the synthesis of enzyme inhibitors  Body.