MCYST-LR Lyophilized pale-yellow solid. 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. Purity: ≥95% by HPLC. RTECS GT2810000, CAS 101043-37-2. Ref.: 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 Toxins 3: Marine Toxins and Venoms (Tu, A.T., Ed.) p. 121, Decker, New York. R: 26/27/28-36/37/38-43; S: 26-36/37/39-45 Not available for sale outside of the United States. |