LC-MS/MS DETECTION AND IDENTIFICATION OF NINE NODULARINS, CYCLIC PENTAPEPTIDES PRODUCED BY THE CYANOBACTERIUM NODULARIA SPUMIGENA

摘要

Nodularin ([6(Z)Adda~3]NOD) is a cyclic pentapeptide hepatotoxin (LD_(50) = 50 μg kg~(-1)) synthesised by a bloom-forming planktonic cyanobacterium Nodularia spumigena. The toxicity of nodularin is associated with inhibition of eukaryotic protein phosphatase type 1 and 2A. The structure of nodularin is cyclo[D-erythro-β-methylAsp(iso-linkage)-L-Arg-Adda-D-Glu(iso-linkage)-2-(methyl-amino)-2(Z)-dehydrobutyric acid], where Adda is the C20 β-amino acid, (2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8,-trimethyl-10-phenyldeca-4(E),6(E)-dienoic acid.