Antibodies directed against synthetic peptides distinguish between the catalytic subunits of protein phosphatases 1 and 2A

Two antipeptide antibodies (designated type 1 antibody and type 2A antibody) were raised against synthetic peptides, Cys -Thr-Pro-Pro-Arg-Asn-Ser-Ala-Lys-Ala-Lys-Lys and Cys -Val-Thr-Arg-Arg-Thr-Pro-Asp-Try-Phe-Leu, corresponding to the carboxyl termini of the catalytic subunits of protein phosphatase 1 and phosphatase 2A ( Cys was added for specific coupling to carrier protein). These antipeptide antibodies were highly specific and were useful in discriminating between protein phosphatase 1 and phosphatase 2A in crude extracts or purified preparations. Type 2A antibody reacted with both native and denatured protein phosphatase 2A whereas under the same condition type 1 antibody reacted only with denatured protein phosphatase 1.