CONSTRUCTION OF AMMONIA METABOLIZING CELL -LINE FOR ARTIFICIAL HYBRIDLIVER SUPPORT SYSTEM USING RECOMBINANT-DNA TECHNIQUES

In order to establish a cell line suitable for a hybrid artificial liv er support system, an ammonia metabolizing activity is given to a Chin ese Hamster Ovary (CHO) cell line using genetic engineering techniques . CHO-K1 cells were transformed with pSV 2-GS vector which contain glu tamine synthetase gene connected with SV 40 promoter. The recombinant cell line was selected under various concentrations of glutamine synth etase inhibitor, methionine sulfoximine (MSX). The 800 mu M MSX tolera ble cell line has high glutamine synthetase activity and can remove am monium from the medium. The kinetic parameters of this cell line were investigated under 0, 1, or 2 mM ammonia concentration. Ammonia consum ption occurred during the middle phase of cultivation (growth phase). The specific ammonium consumption rate of the established cell line du ring growth phase is about one fifth of that of primary hepatocyte.