Greater than 85% of the transport-impaired PiZ variant of human alpha 1-antitrypsin is retained within transfected mouse hepatoma cells and is subjected to intracellular degradation (Le, A., Graham, K., and Sifers, R.N.(1990) J. Biol.Chem.265, 14001-14007).
In this study, we show that there is time-dependent and saturable internalization of alpha 1-AT-elastase and alpha 1-AT-trypsin complexes in human hepatoma HepG2 cells.
In addition, the apparent sizes of native factor I, transferrin, and alpha-1-antitrypsin secreted by the three hepatoma lines differed due to differences in postsynthetic processing.