Purification and Properties of Dextransucrase and Invertase from Streptococcus mutans

Abstract

Invertase (3-D-fructofuranoside fructohydrolase, EC 3.2.1.26) and dextransucrase (a-1, 6-glucan: D-fructose 2-glucosyltransferase, EC 2.4.1.5) were purified from the culture fluids of Streptococcus mutans by chromatography on Sepharose 6B and diethylaminoethyl-cellulose followed by treatment with hydroxyapatite. Each of the enzyme preparations gave a single band when analyzed by either polyacrylamide gel electrophoresis or immunodiffusion. The antigenic determinant of invertase was different from that of dextransucrase on immunodiffusion. The pH optima were 5.25 for invertase and 5.75 for dextransucrase, and the Km

Dark matter in galaxies

“…The 'invisibility' of the gas can be due to both destruction of CO molecules whose radio emission is usually used to estimate the molecular gas content, and a very low temperature of the medium. Part of the gas can be unobservable due to large optical depth of the clouds, which is confirmed by observations [309].…”

“…Generally, the dark gas can constitute a sizable fraction of the total mass of the cold gas in our and nearby galaxies (see the discussion in в [67,309]),]), but it is definitely insufficient to explain DM effects. In addition, if DM indeed concentrates in a plane layer, its thickness must be very high for such a self-gravitating disk to be gravitationally stable.…”

Identification of a 1,3-α glucosyltransferase involved in insoluble glucan synthesis by a serotype c strain of Streptococcus mutans

“…In the soluble glucans, short 1,3-a branches (almost certainly single residues) are attached to a linear 1,6-a dextran, but insoluble glucans contain long sequences of 1,3-a-linked residues that can account for the majority of the glucosidic bonds in the polymer [6,7]. Most strains of S. mutans isolated from carious lesions are serotype c, and dextransucrase, which catalyses soluble glucan synthesis, has been purified from several such isolates [8][9][10]. In contrast, attempts to purify mutansucrase, the enzyme complex responsible for insoluble glucan synthesis, from serotype c strains have failed.…”

“…In contrast, attempts to purify mutansucrase, the enzyme complex responsible for insoluble glucan synthesis, from serotype c strains have failed. This is because mutansucrase activity is associated with an aggregate of various proteins and other extracellular components [8,9,11]. Consequently, the enzyme which catalyses the insertion of sequences of 1,3a-linked glucosyl residues into insoluble glucans has not been identified.…”

Combined extracellular sucrolytic enzyme power from a strain of Streptococcus mutans, and purification results

“…One protein band was very prominent on all gels, and when small amounts of protein were applied, it gave the impression of being a pure protein. This protein may be identical to the one assumed by FuKUi ^^ al. (1974) to be pure dextransucrase.…”