PROCESS OF PB2-CEREVISIAE( ACCUMULATION IN SACCHAROMYCES)

Most of the Pb2+ taken up by Saccharomyces cerevisae was deposited in the inner part of the cells after 2 h. In the Pb2+ accumulation experi ments, the time to reach an equilibrium state was significantly shorte ned from 96 h to 24 h as the cell dry weight increased from 0.56 g/l t o 5.18 g/l. The penetration time of Pb2+ to reach on the interacellula r region (2 h) was quite different from that on the extracellular regi on (3 min). In the case of S. cerevisiae, the first step which a Pb2binds to cell wall within 3 similar to 5 min is metabolism-independent and the second step within 24 h is metabolism-dependent followed by t he third step which is metabolism-dependent or -independent after 24 h .