%0 Journal Article %A Tsumori, Hideaki %T Immunological relationships between glucosyltransferases synthesizing insoluble glucan from Streptococcus cricetus, Streptococcus sobrinus and Streptococcus downei %D 1991 %J Microbiology, %V 137 %N 7 %P 1603-1609 %@ 1465-2080 %R https://doi.org/10.1099/00221287-137-7-1603 %I Microbiology Society, %X Summary: The M r values and isoelectric points of glucosyltransferases synthesizing insoluble glucan (GTF-Is) were determined, and the immunological relationships between them studied. The GTF-I enzymes were from Streptococcus cricetus (mutans group serotype a), Streptococcus sobrinus (mutans group serotypes d and g) and Streptococcus downei (mutans group serotype h). By double immunodiffusion tests, the GTF-I enzymes from the three species possessed a common antigenic determinant; in addition, the GTF-I enzymes of serotypes d, g and h shared a further determinant. The S. sobrinus serotypes d and g GTF-I enzymes were immunologically identical. The GTF-I enzymes of S. sobrinus serotypes d and g, and of S. downei, had an M, of 161000 and isoelectric points of 4·8-4·9, while S. cricetus GTF-I had a lower M r (150000) and a higher isoelectric point (5·2). This suggests that the S. cricetus GTF-I enzyme may lack a sequence of amino acids which include the determinant shared by S. sobrinus and S. downei GTF-I enzymes. Antibodies specific to the determinant shared by all four serotypes inhibited the homologous and heterologous enzymes by 94-100%. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-137-7-1603