抄録
α-Glucan produced by crude dextransucrase (CEP) of Streptococcus mutans E49 was separated into the following three fractions: a water-insoluble glucan fraction (designated as IG), a water-soluble glucan fraction with a wide distribution of molecular weight (SG-1) and an oligosaccharide (SG-2). Formation of these products, which had characteristic courses, were remarkably reduced in the presence of ribocitrin. Production of IG and SG-1 by CEP and the inhibitory activity of ribocitrin were highly pH-dependent. With regard to dextran T10, ribocitrin inhibited IG production competitively.