Echinococcus granulosus, E. multilocularis and mammalian liver-type alkaline phosphatases: a comparative study.

The alkaline phosphatases (EC 3.1.3.1) from Echinococcus granulosus and E. multilocularis (Cestoda) were compared to each other and to a liver-type enzyme. The purified proteins (210 and 220 kDa, respectively) had a tetrameric structure composed of 4, 56/53 kDa subunits. Enzymatic removal of their N-linked sugar moieties abolished the differences in their apparent molecular weight under reducing conditions. After phase separation in Triton X-114, the E. multilocularis enzyme was the most amphiphilic, and treatment with PI-P1C reduced the amount of the parasite alkaline phosphatases that were in a hydrophobic form by about 50%. Both parasite enzymes were highly resistant to heat denaturation and insensitive to the inhibitors L-phenylalanine and L-leucine. In addition, L-homoarginine, levamisole and ZnCl2 can be used to differentiate the parasite and mammalian liver-type enzymes from each other. The Echinococcus alkaline phosphatases have original biochemical properties when compared to the mammalian liver-type enzyme.