The specific release of sialytransferase activity by human hepatoma cell lines.

Sialyltransferase (EC 2.4.99.1) is released in large amounts by two hepatoma cell lines (SK-H-MA and CLH) established from patients with hepatocellular carcinoma (hepatoma). This release requires protein synthesis and glycoprotein synthesis, but not cell division. In contrast, sialyltransferase is released in minimal amounts by a cell line derived from normal human liver (Chang). The hepatoma cells also contain more surface and cellular sialyltransferase activity than Change cells. Hepatoma sialyltransferase has properties similar to other sialyltransferases. Using a calibrated Sephadex G-200 column, it is resolved into two forms with molecular weights of 65 000 and 80 000.