Microcystin analogues comprised only of Adda and a single additional amino acid retain moderate activity as PP1/PP2A inhibitors

A series of greatly simplified microcystin analogues comprised only of Adda (the beta-amino acid common to the microcystins. nodularins, and motuporin,) and a single additional amino acid residue was synthesized and screened for inhibition of the protein phosphatases I and 2A. Several of the analogues were shown to be mid-nanomolar inhibitors of the enzymes. (C) 2003 Published by Elsevier Ltd.