Dextran was synthesized using dextransucrase from Streptococus sanguis 10558 and (F)-[14C]sucrose as substrate to test the possibility that sucrose may be the initial acceptor for glucose. If sucrose is the initial acceptor, then dextran chains should have [14C] fructose in a terminal ‘sucrose’ linkage which can be cleaved under mild conditions. Although incorporation of [14C]fructose into dextran was observed, the label was not released by mild hydrolysis, indicating that sucrose is not the initiator for dextran synthesis. Incorporation of [14C]fructose into dextran might represent its ability to act as an acceptor, as suggested by the isolation of leucrose as a by-product in the reaction.
