Specific method for the purification of Streptococcus mutans dextransucrase

Abstract

A convenient and rapid method for the purification of Streptococcus mutans dextransucrase is described. Affinity chromatography, on a column containing insoluble dextran purified from a culture of S. mutans 6715-49, gave an almost 300-fold purification, with 76% recovery of enzyme. Subsequent hydrophobic chromatography on butyl-agarose increased the overall enzyme purification to more than 1,000-fold, with a 65% recovery of activity. Two components of the dextransucrase activity were separated during hydrophobic chromatography. Both synthesized insoluble glucan as their major product and were capable of synthesizing soluble glucan in the presence of exogenous soluble dextran. However, the major enzyme component, which coeluted with a catalytically inert, dextran-binding protein, was greatly stimulated by exogenous soluble dextran, whereas the second enzyme component was not.