Regulation of Prestalk-specific Acid Phosphatase in Dictyostelium discoideum

Acid phosphatase–2, as characterized by gel electrophoresis under non-denaturing conditions, is a convenient marker for prestalk cells in Dictyostelium discoideum . We have purified this prestalk-specific enzyme and have examined its regulation during development. Under denaturing conditions, the enzyme has a molecular weight of 50,000 and an isoelectric point of 4.0. On the other hand, acid phosphatase-I have a Mr-55,000 polypeptide (AP1–55) and a minor Mr-50,000 polypeptide (AP1–50) and both have diffuse isoelectric point from 3.4 to 4.1. Using monoclonal antibodies directed against acid phosphatase-2 as probes, we showed that some acid phosphatase-2 are newly synthesized at slug stage and some are converted from AP1–50 which was synthesized during ealy development.