Kinetic potentials of certain scavenger enzymes in fresh water snails susceptible and non-susceptible to Schistosoma infection.

The activities of catalase (H2O2-oxidoreductase EC 1.11.1.6)- and glutathione reductase (EC 1.6.4.2) as two important scavenger enzymes, were measured in tissue homogenates of Biomphalaria alexandrina and Bulinus truncatus, the snail vectors of Schistosomiasis. A parallel study was done on Lymnea truncatula snails which are not susceptible to Schistosoma infection. The apparent Michaelis constant (Km) for both anzymes were determined in tissue homogenates of the three studied species. The results obtained showed that both susceptible species have higher affinity to hydrogen peroxide (H2O2) and oxidized glutathione (GSSG) than the non-susceptible one.