Streptococcus mutans Ingbritt sucrose-glucan glucosyltransferase 특성과 그 활성에 미치는 키틴 유도체들의 효과

Characterization of Streptococcus mutans Ingbritt Sucrose-glucan Glucosyltransferase and the Inhibition Effect of Chitin Derivatives on its Activity

충치 형성 과정에 중요한 불용성 글루칸의 합성과 관련된 sucrose-glucan glucosyltransferase (Gtf)를 Streptococcus mutans Ingbritt 의 배양액에서 염석과, Sephadex G-150, CM-Sephadex, DEAE-Sephadex column을 통과시켜 정제하였다. 회수율 6.3%였으며, 정제율 13배였다. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)에서 이 효소의 분자량은 66 kDa이며, 최적 pH와 온도는 각각 6.0과 $40^{\circ}C$이였다. 이 효소는 0.1 mM $Hg^{2+}$, $Cu^{2+}$, $Al^{3+}$에 의하여 22-59% 저해되었다. 이 효소는 2 mM 자이리톨에 의하여 40% 저해 받았으며, 0.05% 수용성 키토산, 글리콜 키토산, 글리콜 키틴에 의하여 35-45% 저해되었다. 키틴 유도체가 Gtf 활성을 억제한다는 보고는 본 연구가 최초이며, 이는 키틴 유도체를 구강청결제의 소재로 활용할 수 있음을 제시한다.

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 $40^{\circ}C$, respectively. The enzyme activity could be inhibited to 22-59% by 1 mM $Hg^{2+}$, $Cu^{2+}$ and $Al^{3+}$, 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.