A Mg2+-independent Ca2+-stimulated ATPase activity in the tegument of Schistosoma mansoni
Cunha, V.M.; Noël, F.
Brazilian Journal of Medical and Biological Research 21(3): 449-451
1988
ISSN/ISBN: 0100-879X PMID: 2976283 Document Number: 316833
A tegumental fraction prepared from S. mansoni exhibited ATPase activity which was stimulated by Ca2+ in the absence of Mg2+. The Mg2+ independency was assessed by lowering contaminant Mg2+ using CDTA. The peak of activity was 220 micro mol Pi/mg protein/h and the K0.5 for CaATP was 0.32 mM; the same K0.5 was obtained using MgATP as substrate, in the absence of Ca2+. Both activities may be promoted by the same enzyme since the addition of Ca2+ did not increase the ATPase activity measured in the presence of a saturating MgATP concentration.