Related Experiment Video
Updated: Aug 16, 2026

Development of a Negative Selectable Marker for Entamoeba histolytica
Published on: December 12, 2010
Membrane bound pyrophosphatases in Entamoeba histolytica
Abstract:
Entamoeba histolytica homogenates are capable of hydrolyzing a range of inorganic and organic pyrophosphates. Two separate activities are present: an inorganic pyrophosphatase hydrolyzing inorganic pyrophosphate and linear tripolyphosphate, and a nucleoside diphosphatase hydrolyzing thiamine pyrophosphate and nucleoside diphosphates (ADP, GDP and UDP). The inorganic pyrophosphatase has an acid pH optimum, a relatively high KM (congurent to 1 micrometer) and is markedly heat stable and lacks a metal requirement. The nucleoside diphosphatase also has an acid pH optimum but displays a much higher affinity for substrate (KM congurent to 50 micrometer), is unstable to heating and is activated by Ca ions. Both pyrophosphatases distinct from the acid phosphatase activity which is also present. All three hydrolases are sedimentable and latent suggesting their association with membrane bounded organelles. No soluble inorganic pyrophosphatase activity could be demonstrated.
Related Concept Videos
Membrane Asymmetry Regulating Transporters
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Diversity of Archaea IV
Fungal Phylum Microsporidia
Diversity of Protists I
Diversity of Protists IV
Amebiasis

