Studies of placental alkaline phosphatase by means of lectin affinity electrophoresis

1) The author has developed a new type of lectin affinity electraphoresis (AEP) using polyacrylamide-gel (PAG) with Lentil-lectin (LCH) as the affinity ligand. By this method, placental alkaline phosphatase was separated into 4 distinct bands (PLALP I ～IV subgroups) with different affinity for LCH. 2) According to affinity constants theory, the dissociation constants of PLAP-LCH interaction were determined. The obtained dissociation constants revealed that PLALP I has the strongest affinity for LCH and PLALP IV has the weakest affinity. 3) The author has also developed a two dimensional affinity electrophoresis (1st. Dimention : isoelectric focusing, 2nd. Dimention : lectin AEP). By this method, each PLALP subgroup was further separated into 5～6 fractions having different isoelectric point. The origin of the PLALP polymorphism in AEP was based on the affinity of the enzymes for LCH.