Isolation and properties of ribocitrin.

Abstract

A dextransucrase inhibitor, ribocitrin, was purified about 580-fold from a culture broth of Streptomyces neyagawaensis MF980-CF1 by combination chromatography.Ribocitrin is a previously unknown type of oligosaccharide composed of ribose. It inhibited the crude preparation of dextransucrase noncompetitively with regard to sucrose and the inhibitory activity (Inh%) was sensitive to pH. It was very stable at alkaline pH values, but gradually lost its inhibitory activity as the acidity increased. It had no antimicrobial activity. It did not inhibit glycoside hydrolases and was not susceptible to the above enzymes. It had a low toxicity.Plaque formation of Streptococcus mutans E49 on a smooth glass surface was diminished by ribocitrin and the colony form of this microorganism on Mitis Salivarius agar was evidently affected by ribocitrin.