title: Purification and characterization of extracellular glucosyltransferase from Streptococcus mutans serotype b (subspecies rattus).
abstract: An extracellular glucosyltransferase (GT-S) synthesizing water-soluble glucan was purified from the culture supernatant of Streptococcus mutans BHT (serotype b, subsp. rattus) by DEAE-Sepharose chromatography and preparative isoelectric focusing. The Mr of the enzyme was 155,000 and the pI was 4.5. The GT-S had a specific activity of 10.2 i.u. (mg protein)-1, an optimum pH of 6.0 and a Km value of 0.8 mM for sucrose, and was activated twofold by dextran T10. The GT-S was immunologically partially identical with the corresponding enzymes in crude preparations from serotypes c, e and f. The glucan synthesized de novo from sucrose by the GT-S was water-soluble and consisted of 29 mol% of non-reducing terminal, 49 mol% of 1,6-alpha-linked, 11 mol% of 1,3-alpha-linked and 11 mol% of 1,3,6-alpha-branched glucose residues.
mesh_terms: D000818:Animals; D002852:Chromatography, Ion Exchange; D005964:Glucosyltransferases / Q000302:isolation & purification*; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D051381:Rats; D013295:Streptococcus mutans / Q000201:enzymology*
chemical_list: D005964:Glucosyltransferases