EINECS: 200-158-2

  Molecular formula: C3H7NO2S

   Molecular formula: cysteine HSCH2CH (NH2) COOH,

      Molecular weight: 121.15

      Solubility in water: 277.433 g / L (25 ° C, water)

      Solubility: soluble in dilute inorganic acid and alkaline solution, not easily soluble in water, insoluble in ethanol, insoluble in ether and chloroform.

  Cysteine, a common amino acid in the body, can be converted from the body methionine (methionine, essential amino acids). Cysteine and cystine can be transformed into each other.

      HSCH2CH (NH2) COOH, (C3H7NSO2) is one of sulfur-α-amino acids,  with nitroprusside it becomes  purple (due to SH). It exists in many proteins, glutathione, with Ag, Hg , Cu and other metal ions it can form insoluble thiolate (mercapti-de), which are R-S-M ', R-S-M "-S-R (M', M" each is a monovalent, divalent metal). Cysteine is a non-essential amino acid in human body. In the animal body it is from methionine and serine through the cystathionyl to synthesis. Inorganic sulfur (from sulfate) imported into cysteine, in plants and bacteria, from sulfuric acid through 3 '- adenosine phosphate - 5' - phosphate and sulfurous acid sulfate to generate H2S, which reacts with O - acetyl serine or serine and generated.