Merck, 475815-500UG, Microcystin-LR, Microcystis aeruginosa

General description
Cyclic heptapeptide toxin isolated from the freshwater cyanobacteria Microcystis aeruginosa. Potent inhibitor of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A). Unlike Okadaic Acid (Cat. No. 495604), microcystin-LR is effective on both PP1 (IC₅₀ = 1.7 nM) and PP2A (IC₅₀ = 40 pM). Reacts with phosphatase in a two-step mechanism involving rapid binding and inactivation of the catalytic subunit followed by slower covalent interactions. Has no effect on protein kinases, making it useful for reducing the effect of contaminating phosphatase activities in protein kinase assays. A 2.5 mM (250 µg/100 µl) solution of Microcystin-LR, Microcystis aeruginosa (Cat. No. 475821) in DMSO is also available.
Biochem/physiol Actions
Target IC₅₀: 1.7 nM and 40 pM against PP1 and PP2A, respectively
Preparation Note
Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C. Unstable at > pH 7.7.
Further dilute with aqueous buffer just prior to use.
Other Notes
Craig, M., et al. 1996. Biochem. Cell Biol. 74, 569.
Nishiwaki, R., et al. 1994. Cancer Lett. 83, 283.
Amick, G.D., et al. 1992. Biochem. J.287, 1019.
Davidson, H.W., et al. 1992. J. Cell Biol.116, 1343.
Nishiwaki-Matsushima, R., et al. 1992. J. Cancer Res. Clin. Oncol. 118, 420.
Cohen, P., et al. 1990. Trends Biochem. Sci.15, 98.
MacKintosh, C., et al. 1990. FEBS Lett.264, 187.
Cohen, P., et al. 1989. FEBS Lett.250, 596.
Carmichael, W.W. 1988. in Handbook of Natural Toxins3: Marine Toxins and Venoms(Tu, A.T., Ed.) p. 121, Decker, New York.
Legal Information
CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany
Disclaimer
Toxicity: Highly Toxic (H)