The release of high-molecular-weight alkaline phosphatase and leucine aminopeptidase into the media of cultured human cells.

Using exclusion from Sepharose 4B as our criterion, we have found a high-molecular-weight form of alkaline phosphatase and of leucine aminopeptidase which are released into the culture media by the FL amnion cell line. A low-molecular-weight form of leucine aminopeptidase is also found to contribute to the total levels of this enzyme in the media. The levels of these enzymes increased during the growth cycle of the culture, paralleling the increase in cell density, suggesting that the two events may be related. This phenomen in culture suggests a possible explanation for the appearance of similar enzyme forms in patient serum and fluids originating from diseased tissue.