Characterization of Streptococcus mutans Ingbritt Sucrose-glucan Glucosyltransferase and the Inhibition Effect of Chitin Derivatives on its Activity
2012
Ju, W.T., Chonnam National University, Gwangju, Republic of Korea | Ji, M.S., Yeongam-Gun Agricultural Technology Center, Yeongam, Republic of Korea | Park, R.D., Chonnam National University, Gwangju, Republic of Korea
Sucrose-glucan glucosyltransferase (Gtf) is an important enzyme involved in the cavity formation process where insoluble glucan is synthesized. In this study, we purified Gtf from Streptcoccus mutans Ingbritt through ammonium sulfate precipitation, Sephadex G-150, CM-Sephadex, and DEAE-Sephadex column chromatographies. A 13-fold of purification was achieved with a total yield of 6.3%. The apparent molecular mass of the enzyme was determined to be 66 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and temperature were established to be 6.0 and 40℃, respectively. The enzyme activity could be inhibited to 22-59% by 1 mM Hg²+, Cu²+ and Al³+, and to 68% by 1 mM EDTA. It was also inhibited 40% by 2 mM xylitol and 35-45% by 0.05% soluble chitosan, glycol chitosan, and glycol chitin. This is the first report to reveal the inhibition effect of chitin derivatives on Gtf activity, which may be further applicable to develop gargles to overcome cavity.
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