Abstract
The cellular localization of cancer-associated alkaline phosphatase is studied in three cultured human cancer cell lines, which are established as monophenotypic to early placental in KMK-2, Kasahara in HeLa S3-5, and Regan isozymes in HeLa S3-10 respectively.
First, it is confirmed that the optimal conditions of the cell fixation, the substrate concentration and the cultured method, as factors which influenced on the electron cytochemical demonstration of alkaline phosphatase should be thoroughly studied cell-line to cell-line in order to accurately interpret the localization of each isozyme concerned.
Second, it is shown that all of the enzyme activities of the early placental, Kasahara and Regan isozymes are located on the whole plasma membrane, particularly the outer lamella and the spaces between the outer and inner lamellae. However, it is less certain that the reaction products in some intracytoplasmic organelles of KMK-2 and HeLa S3-5 are the specific sites of the early placental isozyme or the Kasahara isozyme. Effects of some activators and inhibitors to each isozyme on the enzyme activity and the cellular localization are also described.
