HIGH-MOLECULAR-WEIGHT PRECURSORS OF GLUCANS IN SACCHAROMYCES-CEREVISIAE

Nascent beta-1,3 glucan synthesized by mixed membrane fractions from S accharomyces cerevisiae was solubilized by extraction with hot SDS or urea. Nature of the material was analyzed by electrophoresis and gel f iltration. As determined by gel filtration, Mr of synthesized glucans exceeded 1,500 kDa, but was below 20,000 kDa. This nascent material se rved as an acceptor for further glucose transfer reactions, giving ris e to glucan molecules over 20,000 kDa. It is suggested that the high M r precursor components represent protein-bound glucan molecules in tra nsit to the cell surface.