Open AccessPurification and Properties of Extracellular Glucosyltransferase Synthesizing 1,6-, 1,3- -D-Glucan from Streptococcus mutans Serotype a
Author(s) -
Hideaki Tsumori,
Atsunari Shimamura,
Hidehiko Mukasa
Publication year - 1985
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-131-12-3347
Subject(s) - glucosyltransferase , streptococcus mutans , glucan , microbiology and biotechnology , serotype , extracellular polysaccharide , extracellular , chemistry , polysaccharide , biology , biochemistry , bacteria , enzyme , genetics
An extracellular glucosyltransferase (sucrose: 1,6-, 1,3-alpha-D-glucan 3-alpha- and 6-alpha-D-glucosyltransferase, EC 2.4.1.-) of Streptococcus mutans HS6 (serotype a) was purified from culture supernatant by DEAE-Sepharose chromatography and preparative isoelectric focusing. The molecular weight measured by SDS-PAGE was 159 000 and the isoelectric point was pH 4.9. The specific activity was 89.7 i.u. (mg protein)-1 and the optimum pH was 6.0. The Km value for sucrose was 4.9 mM and the enzyme activity was not stimulated by exogenous dextran T10. Glucan was synthesized de novo from sucrose by the purified enzyme and consisted of 49.1 mol% 1,6-alpha-linked glucose and 33.9 mol% 1,3-alpha-linked glucose, with 13.6 mol% terminal glucose and 3.3 mol% 1,3,6-alpha-branched glucose.