Jeang C L, Lee Y H, Chang L W
Department of Food Science, National Chung Hsing University, Taichung, Taiwan.
Biochem Mol Biol Int. 1995 Mar;35(3):549-57.
A newly isolated bacterium from soil, identified as Cytophaga sp. was found to produce raw-starch digesting amylase. The enzyme was purified from 24-hr cultured medium through ammonium sulfate fractionation, DEAE-Sepharose CL 6B ion exchange chromatography and Sephacryl S-200 gel filtration. The preparation was proved to be homogeneous by SDS-PAGE. The subunit molecular weight determined by SDS-PAGE was 59 KD. The optimum temperature was 50 degrees C on soluble starch and 60 degrees C on raw starch. The optimum pH was in the range of 4.5 to 6.5 on soluble starch and 6.5 to 9.5 on raw starch. In the presence of Mn+2, Cu+2 or Zn+2, the enzyme activity on either substrate was inhibited. Dinitrofluorobenzene, N-bromosuccinimide and trinitrobenzene sulfonic acid all showed inhibitory effect on the enzyme acting on both substrates.
从土壤中新分离出的一种细菌，经鉴定为噬纤维菌属，被发现能产生消化生淀粉的淀粉酶。该酶通过硫酸铵分级沉淀、DEAE-琼脂糖CL 6B离子交换色谱和Sephacryl S-200凝胶过滤从24小时培养的培养基中纯化出来。通过SDS-PAGE证明该制剂是纯的。通过SDS-PAGE测定的亚基分子量为59 KD。在可溶性淀粉上的最适温度为50℃，在生淀粉上为60℃。在可溶性淀粉上的最适pH范围为4.5至6.5，在生淀粉上为6.5至9.5。在存在Mn+2、Cu+2或Zn+2的情况下，该酶对任何一种底物的活性均受到抑制。二硝基氟苯、N-溴代琥珀酰亚胺和三硝基苯磺酸对该酶作用于两种底物均显示出抑制作用。
