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, and 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.