Polycarboxylates inhibit the glucan-binding lectin of Streptococcus sobrinus

Polycarboxylates, such as carboxymethylcellulose and hyaluronan, were found to be reversible inhibitors of the glucan-binding lectin of Streptococcus sabrinus. When the carboxylate groups were coupled to ethylenediamine, or r educed with carbodiimide-borohydride, inhibitory powers were lost. Similarl y, N-deacetylated hyaluronan had poor inhibitory powers, probably due to th e introduction of positive charges into the polymer. Other polymers, such a s chondroitin sulfates, dextran sulfate, fetuin, heparin were not inhibitor s. It appears that inhibition is based on repeating carboxylates, free of i nfluence from ammonium groups. Such polymers have the property of complexin g with metals. Earlier studies had concluded that the streptococcal lectin depended on manganese for activity. It is likely the carboxymethylcellulose and hyaluronan perturb essential metal coordination centers in the lectin. Polycarboxylates may have value in oral health care by acting on glucan-de pendent microbial adhesion and biofilm formation. (C) 2000 Elsevier Science B.V. All rights reserved.