福岡県農業総合試験場研究報告

う蝕原性レンサ球菌の産生する菌体遊離型Glucosyltransferaseの活性評価とその活性に及ぼす農産物抽出物の影響

[摘要］Streptcoccus mutans MT8148をファーメンターで培養し、調製した粗菌体遊離型Glucosyltransferase(CF-GTase）は、精製酵素と同様の酵素化学的特性を有した。調製した粗CF-GTase液を用いて、各種農産物抽出物のCF-GTase活性抑制効果について検討したが、CF-GTaseの活性を抑制したのは、イチジクのみであった。イチジクの品種の中では、‘イスキア・ブラック’と‘蓬莱柿’が不溶性グルカンの生成を抑制した。‘イスキア・ブラック’を2000μｇ/ml添加すると、無添加の場合に比べて不溶性グルカンの生成が30％以下に抑制された。また、イチジクに特徴的な成分であるペクチン及びα-D-ガラクツロン酸は活性抑制効果を示し、イチジク抽出物のCF-GTase活性抑制効果とペクチン含量との間に相関が認められた。

［キーワード：Streptococcus mutans MT8148、菌体遊離型Glucosyltransferase、イチジク、‘イスキア・ブラッグ、‘蓬莱柿’、ペクチン］

　Characterization of Cell-free Glucosyltransferase from Streptococcus mutans, and Effects of Extracts from Some Edible Plants on Cell-free Glucosyltransferase. NORIMURA Naoko and Sumitaka YAMASHITA (Fukuoka Agricultural Research Center, Chikushino, Fukuoka 818-8549, Japan)Bull.Fukuoka Agric.Rec.Cent., 18: 96 - 100 (1999)

　Crude cell-free glucosyltransferase(CF-GTase) which was obtained from incubating Streptococcus mutans MT8148 with a fermenter had a characterization similar to a purified enzyme. The effects of extracts of some edible plants on the crude CF-GTase were examined . It was found that the extracts of fig inhibited the activity of CF-GTase. The highest effect on the inhibition of water-insoluble glucan synthesis was shown in the extract of 'ISCHIA BLACK' and　'HOURAISHI', fig cultivars. The extract of 'ISCHIA BLACK' reduced water-insoluble glucan production down to 30% at concentrations of 2000μg/ml, compared with the control. The activity of CF-GTase was inhibited by pectins and α-D-galacturonic acid, which were the main components of the figs. The inhibitory effects of extracts from figs and the content of pectin showed a significant correlation.