Table 1. Microcystin-LR degradation products identified by ESI(+) MS/MS.

m/z	Composition and sequence
218.2125 (I)	Leu-MeAsp – (NH2) Or Adda – (−134 Adda) + (2 OH)
274.2769 (II)	Arg-MeAsp – (NH) + (O)
302.3074 (III)	Glu-Mdha – (CH2) + (O)
318.2028 (IV)	Arg-MeAsp + (2 O)
540.5383 (V)	Arg-MeAsp-Leu-Ala-Mdha-Glu
851.3981 (VI)	Cyclo[Adda-Glu-Mdha-Ala-Leu-MeAsp-Arg-Adda] – (177Adda) + (O) + (OH)