Degradation of dextrans by an α-1,6-glucan glucohydrolase from Streptococcus mitis

摘要: Abstract A dextran-glucosidase (α-1,6-glucan glucohydrolase) found in cell extracts of several strains Streptococcus mitis has been purified, and some its properties have investigated. Dextran-glucosidase hydrolysed isomaltose saccharides at comparable rates, a comparison K m values for isomaltose, isomalto-pentaose dextran showed that the enzyme had equal affinity these substrates despite their different chain-length. The action pattern was not completely characteristic an exo-glucanase or glucosidase. Its ability to act on polymers, complete specificity α-(1→6)- D -glucosidic linkages were associated with exo-glucanases, whereas transferring ability, retention configuration, inhibition by nojirimycin supported classification as Dextrans incompletely degraded enzyme, extent hydrolysis being related proportion linkages. It concluded α-(1→4)- α-(1→3)-, α-(1→2)- occur bacterial dextrans resistant dextran-glucosidase, arrested further enzymic degradation dextran. use investigations fine structure is discussed.