摘要:The ability of oral streptococcal species to bind transferrin was determined using an assay system in which the binding of fluorescein isothiocyanate-labelled transferrin was monitored by measuring the decrease in fluorescence using excitation and emission wavelengths of 495 nm and 525 nm, respectively. Transferrin was bound by all species tested but Streptococcus oralis and Streptococcus mitis exhibited the greatest affinity and the mutans streptococci the least. Transferrin binding to S. oralis was inhibited by fetuin but not by N-acetylneuraminic acid or bovine N-acetylneuramin lactose. Transferrin binding by S. oralis and S. mitis may be involved in their initial attachment to the tooth surface and in their nutrition.Keywords: Transferrin binding; Oral streptococci; Streptococcus orah; Siak acid.