AGGREGATED FORM OF DEXTRANSUCRASES FROM LEUCONOSTOC-MESENTEROIDES NRRL B-512F AND ITS CONSTITUTIVE MUTANT

Purified dextransucrases [EC 2.4.1.5], DSW-D and DSW-G, from Leuconost oc mesenteroides B-512F were obtained from affinity chromatography wit h DEAE-Sephadex A-50 by elution with clinical dextran and guanidine-HC l, respectively, DSM-G was purified from the B-512F mutant strain SH 3 002, which produces dextransucrase constitutively, Although the sugar contents of the purified enzymes were different, their molecular masse s by SDS-PAGE were all 170kDa, DSW-D and DSW-G were highly aggregated and the all the activities were eluted at the void volume (V-o) on Sep harose 6B, while the DSM-G was eluted at 1.2 x V-o volume, On rechroma tography, DSM-G was separated into three peaks corresponding to the ag gregated form, monomeric form, and partially digested form, respective ly, The aggregation of Leuconostoc dextransucrase was looser than that of streptococcal glucosyltransferases, but the structures of these en zymes had high homology with each other.