Rapid purification of protein phosphatase 2A from mouse brain by microcystin-affinity chromatography.

Microcystin LR, which is a monocyclic heptapeptide containing two L-amino acids, leucine and arginine, is a new inhibitor of protein phosphatases 1 and 2A. Microcystin LR-affinity chromatography was used to purify protein phosphatase 2A as a holoenzyme. Five mg of microcystin LR were immobilized to ECH Sepharose 4B by the carbodiimide coupling reaction. Following DEAE-cellulose column chromatography, microcystin-affinity chromatography, as the second step in the procedure, resulted in purification of protein phosphatase 2A in a pure form. The enzyme isolated from mouse brain consisted of two regulatory subunits of 67 kDa and 58 kDa and a catalytic subunit of 41 kDa. Microcystin-affinity chromatography is useful for isolation of protein phosphatase 2A.