Functional molecular size and structure of dextransucrase by radiation inactivation and gel electrophoresis

Identification and functional characterization of levS, a gene encoding for a levansucrase from Leuconostoc mesenteroides NRRL B-512 F

“…In the three dimensional structure of levansucrase from B. subtillis (Miller and Robyt, 1986), the presence of a Ca 2+ binding site has been suggested and although the role of this cation in the catalysis is not clear, in vitro thermal refolding data, demonstrated that Ca 2+ and other cations are able to shift the equilibrium from the unfolded to the folded state, stabilizing the enzyme. Calcium is also a stabilizing agent for both levansucrase and inulosucrase from L. reuteri (Ozimek et al, 2005).…”

“…However, since 1979 it has been reported that levansucrase is also present in dextransucrase preparations obtained from the industrial strain L. mesenteroides B-512 F (Robyt and Walseth, 1979). In a later report, Miller and Robyt (1986) described two FTFs of 116 and 92 kDa but due to their low activity, their properties have not been studied. Recently, Kang et al (2005), have reported the isolation of a L. mesenteroides B-512 FMC levansucrase gene (m1ft).…”

“…1). As already reported by Miller and Robyt (1986) two main bands exhibiting FTF activity with molecular masses between 116 and 92 kDa were observed, and the upper band was selected for peptide micro sequencing. From the sequenced peptides DVADNIASLNPDTSV and VLDTV-LAQGTXTYDG, the degenerate primers Pep1 and Pep2 were designed and a 1211-bp fragment (probe A) generated by PCR techniques from chromosomal DNA as template.…”

Proteolytic processing of dextransucrase of Leuconostoc mesenteroides

“…Molecular masses of DS have been reported, ranging from 64 to 185 kDa [4]. This variation has been associated with the presence of dextran in the puri¢ed preparations, with the disassociation of subunits from a high molecular mass multimeric complex [5^7] or with the action of proteases [8,9], although until now no protease has been reported in L. mesenteroides. Recently, Smith and Zahnley [10] reported that the various molecular mass forms of alternansucrase (a glucosyltransferase closely related to DS) produced from constitutive mutants of L. mesenteroides NRRL B-1355, were not related to dextran.…”

Optimization of Process Parameters for Maximum Production and Characterization of Dextransucrase From Newly Isolated Acetobacter Tropicalis

“…Aliquots (1 mL) from the reaction mixture were analyzed for reducing sugar by DNS (dinitro salicylic acid) method (Miller, 1959). Activity of dextransucrase from A. tropicalis was expressed in terms of units (U/mL).…”