Studies on dextrans and dextranases. 3. Structures of oligosaccharides from Leuconostoc mesenteroides (Birmingham) dextran

Abstract

The dextranases of Penicillium lilacinum (LM.L-79197; NRRL-896) (dextranase-A) and P. funiculosum (I.M.I. -79195; NRRL-1132) (dextranase-B) hydrolyze L. mesenteroides (Birmingham) dextran to complex mixtures of oligosaccharides. The "branched" oligosaccharides were members of an homologous series. The tetrasaccharide produced by dextranase-B was 33-[alpha]-glucosylisomaltotriose. The pentasaccharides produced by dextranases-A and-B were identical and were a 33 -gluco-sylisomaltotetraose alone or in admixture with 3 -glucosylisomaltotet-raose. The hexasaccharides were identical and were 33-glucosyliso-maltopentaose alone or in admixture with isomers in which the branching occurred further towards the non-reducing end of the isomaltopentaose unit. The heptasaccharide and octasaccharide produced by dextranase-A contain 3 -glucosylisomaltohexaose and 3 -glucosylisomaltoheptaose respectively. Both saccharides could have been in admixture with isomers in which the branching occurred further towards the non-reduc-ing end of the isomalto-hexaose and -heptaose units respectively. The octasaccharide also contained a saccharide in which 2 glucose units are joined through (1[long dash][forward arrow]3)-linkages to isomaltohexaose.