Purification and properties of Streptococcus mutans extracellular glucosyltransferase

Three kinds of extracellular glucosyltransferases from Streptococcus mutans 6715 (serotype g)

“…Analytical isoelectric focusing (IEF) was carried out on the gel as in [8,11], with 1% Triton X-100 [12]. An 8 pl amount of culture supernatant was directly applied to a filter paper on the gel surface.…”

“…Another gel was incubated in 5% sucrose containing 12 PM dextran TlO. The last gel was incubated in 5% sucrose and then treated with 1Opg exodextranase from Penicillium funiculosum at 37°C for 6 h in 100 ml of 0.1 M sodium acetate buffer (pH 5.5), as used in [8]. The activity stain was described above.…”

“…Glucans were synthesized as in [8] except for 4 days. The enzyme preparations used were the 7 fractions of p1 5.5-7.0 and the 1,3_cw-D-glucan synthetase of p1 4.9, which were obtained by a preparative IEF.…”

“…The purification and properties of the enzyme in multiple forms (p1 5.5-7.0) will be reported elsewhere. Each of the glucans was collected as a 75% ethanol precipitate [8]. The glucan synthesized by the 1,3_cr-D-glucan synthetase was collected as a water-insoluble glucan by centrifugation.…”

“…The highly-branched 1,6_cu-D-glucan synthetase (sucrose : 1,6_cY-D-glucan ~-LY-and 6_cy-glucosyltransferase) [8] and the 1,3_cu-D-glucan synthetase (sucrose : 1,3-cr-D-glucan 3_clu-glucosyltransferase) [9] have been purified from S. mutuns 6715. However, both of the two distinct enzymes have required an exogenous primer or acceptor such as dextran for the full expression of their essential activities, indicating that the two enzymes alone could not be enough to synthesize the adhesive insoluble glucan in vivo.…”