Ali Ehab M M
Biochemistry Division, Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.
Exp Parasitol. 2008 Jun;119(2):285-90. doi: 10.1016/j.exppara.2008.03.004. Epub 2008 Mar 21.
Nucleotidase cascades (apyrase, 5' nucleotidase, and adenosine deaminase (ADA) were investigated in the parasitic trematode Fasciola gigantica. ADA had the highest activity in the nucleotidase cascades. Adenosine deaminase was purified from F. gigantica through acetone precipitation and chromatography on CM-cellulose. Two forms of enzyme (ADAI, ADAII) were separated. ADAII was purified to homogeneity after chromatography on Sephacryl S-200. The molecular mass was 29 KDa for the native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme (ADAII) had a pH optimum at 7.5 and a K(m) 1.0 mM adenosine, a temperature optimum at 40 degrees C and heat stability up to 40 degrees C. The order of effectiveness of metals as inhibitors was found to be Hg(2+)>Mn(2+)>Cu(2+)>Ca(2+)>Zn(2+)>Ni(2+)>Ba(2+).
对寄生吸虫巨片形吸虫中的核苷酸酶级联反应（三磷酸腺苷双磷酸酶、5'-核苷酸酶和腺苷脱氨酶（ADA））进行了研究。ADA在核苷酸酶级联反应中活性最高。通过丙酮沉淀和CM-纤维素柱层析从巨片形吸虫中纯化出腺苷脱氨酶。分离出两种酶形式（ADAI、ADAII）。ADAII经Sephacryl S-200柱层析后纯化至均一。使用凝胶过滤和SDS-PAGE分别测得天然酶和变性酶的分子量为29 kDa。该酶（ADAII）的最适pH为7.5，腺苷的K(m)为1.0 mM，最适温度为40℃，热稳定性可达40℃。发现金属作为抑制剂的有效性顺序为Hg(2+)>Mn(2+)>Cu(2+)>Ca(2+)>Zn(2+)>Ni(2+)>Ba(2+)。
