title: Purification and properties of extracellular glucosyltransferase synthesizing 1,3-alpha-D-glucan from Streptococcus mutans serotype a.
abstract: Extracellular 1,3-alpha-D-glucan synthase (sucrose: 1,3-alpha-D-glucan 3-alpha-D-glucosyltransferase, EC 2.4.1.-) of Streptococcus mutans HS6 (serotype a) was purified from culture supernatant by ultrafiltration, DEAE-Sepharose chromatography and preparative isoelectric focusing. The enzyme had a molecular weight of 158 000 by SDS-PAGE and an isoelectric point of pH 5.2. The specific activity of the enzyme was 48.3 i.u. (mg protein)-1. The Km for sucrose was 1.2 mM and the activity was optimal at pH 6.0. The enzyme activity was stimulated about 20-fold in the presence of dextran T10. Glucan was synthesized de novo from sucrose by the enzyme and characterized as a linear 1,3-alpha-D-glucan by GC-MS.
authors.forename: H
authors.initials: H
authors.lastname: Tsumori
authors.forename: A
authors.initials: A
authors.lastname: Shimamura
authors.forename: H
authors.initials: H
authors.lastname: Mukasa
mesh_terms: D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005936:Glucans / Q000096:biosynthesis; D005964:Glucosyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D005779:Immunodiffusion; D007525:Isoelectric Focusing; D013295:Streptococcus mutans / Q000201:enzymology*; D014462:Ultrafiltration
chemical_list: D005936:Glucans; C045788:alpha-1,3-glucan; C036655:1,3-alpha-D-glucan synthase; D005964:Glucosyltransferases