L-Cysteine, E920, CAS No.52-90-4, a non-essential amino acid manufactured through fermentation. Cysteine is extracted from raw materials of animal and human origins. Cysteine has the same structure as serine, but with one of its oxygen atoms replaced by sulfur. As an experienced L-Cysteine manufacturer and supplier, we has been supplying and exporting L-Cysteine for almost 10 years, please be assured to buy from us. Any inquiries about price and the market trend please feel free to contact us, we will reply you within 1 working day. Categories Amino Acids Qty in 20â??FCL 12000kg Min Order 500kg Origin China Packaging Factory Packaging or Neutral Certificate ISO, Kosher, Halal, BRC E No. E920 CAS No. 52-90-4 HS Code 293090 Specification FCC/USP L-Cysteine Specification Item Specifications (AJI97 ) Appearance White crystal or crystalline powder; tasteless Assay, % 98.5~101.0 Specific rotation -218~ -224 Loss on drying, % 0.2 Transmittance, % 98.0 Chloride (as Cl), % 0.02 Sulfate (as SO4), % 0.02 Ammonium as (as NH4), % 0.02 Iron (as Fe), % .001 Heavy Metals (as Pb), % 0.001 Arsenic (as As), % 0.0001 pH Value 5.0~6.5 Residue on ignition, % 0.1 Other amino acid Conforms