Abstract
Biosynthesis and secretion of HTGL were investigated by using human hepatoma cell line, Hep G2. The cells were labeled with 35S-methionine and the labeled HTGL was specifically immunoprecipitated with monospecific anti-human HTGL antibody. The immunocomplexes were analized by SDS-PAGE and autofluolography. Hep G2 was cultured in the presence and absence of heparin. Two distinct labeled HTGL protein band having molecular size of 62kDa and 65kDa were detected in cells, but no HTGL protein band was observed from culture medium in the absence of heparin. The synthesized HTGL protein (65kDa) was released with heparin (10 units per ml) into the culture medium, while the HTGL protein (62kDa) was not released. These results suggested that HTGL was synthesized as a catalytically active form having a molecular size of 62kDa protein and posttranslationally processed to the 65kDa protein which is released by heparin.
