Acid phosphatases of the human placenta, characterization and immunological comparison with prostatic acid phosphatase.

Four different acid phosphatases, denoted A1, A2, B and C, were separated from human placental homogenates. The enzymes A1, A2 and B were separated from enzyme C by binding to concanavalin A-Sepharose. Although the A1, A2 and B enzymes were all strongly inhibited by L-tartrate, only the A1 enzyme bound by affinity chromatography to L-tartrate-Sepharose. The A2 and B enzymes were separated on DEAE-cellulose. A1, A2 and B had molecular weights about 95,000. Enzyme B had high KM, whereas enzymes A1 and A2 had low KM. The enzymes A1 and A2 bound to antibodies raised against prostatic acid phosphatase, whereas the enzymes B and C did not.