국내에서 구입 가능한 주요 식이 소재로부터 장내의 대표적인 유해균인 Clostridium perfringens의 생육을 억제시키는 소재를 탐색한 결과 감자즙에서 강력한 항균활성을 발견하였다. 감자즙 중 70% 황산암모늄용액에서 침전되는 단백질성 물질이 항균활성을 나타낸 것으로 밝혀졌으며, 이 감자단백질은 pH 4~10 사이에서는 안정하나 $60^{circ}C$에서 10분간의 열처리로 그 활성이 소실되었다.
Potato juice was found out to have a strong inhibition activity on the growth of Clostridium perf;nngens during work of foodstuffs for the improvement of human intestinal microflora. The anti-bacterial activity of the precipitated protein obtained from the potato juice in 70% ammonium sulfate solution was stable at the range of pH 4 to 10, whereas it was lost by a heat treatment at $60^{circ}C$ for 10 min. The minimal inhibitory concentration of the precipitated protein on the growth of C1. Pefingens was about 0.2 mg/ml. The potato protein also suppressed the growth of C1. butyrincm and Eubacterium iimosum, while it showed a promoting effect for the growth of Bifdobacterium bifidum, Bif: animalis, Lactobacillus plantarum and Lact. acidophitus. The potato protein was further purified by CM-Sepharose ion exchange column chromatography, Sephadex G-150 gel filtration column chromatography and SDS-polyacrylarnide gel electrophoresis. The purified protein(kCp) was proved to be a glycoprotein by PAS staining and its molecular weight was about 38.7 kd.
