ADDA (amino acid)
ADDA is a non-proteinogenic amino acid found in toxins made by cyanobacteria. Toxins which include this amino acid include microcystins and nodularins.
Along with leucine and arginine, it is found in microcystin-LR, an extremely toxic compound produced by cyanobacteria. In order to treat a water supply contaminated with microcystin-LR, chlorination can be used to oxidize the double bonds of ADDA in order to initiate the chemical breakdown of this compound.