Inhibitor of PP1 and PP2A

Isolated from Microcystis aeruginosa.

Microycystin-LR is a naturally occuring heptapeptide ester hepatotoxin and has been seen to be one of the most toxic within the Microcystin family. Studies have also revealed this toxin can act as a tumor promoter by selectively inhibiting protein phosphatase 1 (PP1) and 2A (PP2A). PP2B is less sensitive and PP2C is not inhibited up to 4 µM. This product is useful for affinity-purification of PP2A. It is not cell permeable except in liver cells, which appear to have a functional uptake system. Is absorbed by hepatocytes via the multispecific organic anion transporter. Does not induce any effects on mouse skin or human fibroblasts due to cell membranes impermeability. Has no effect on protein kinases. Less toxic than the more hydrophobic analogs microcystin-LY, -LW and -LF.

Microcystin-LR has been frequently found as a contaminate to fresh-water lakes and ponds causing a major negative impact. This product can be used as an analytical standard (reference substance) for water testing. The product can also be used a very pure Microcystin-LR in studying its interaction with the protein phosphatases.