An extracellular monoADP-ribosyl transferase activity in Entamoeba histolytica trophozoites.

Due to the important role of monoADP-ribosyl transferases in physiological and pathological events, we investigated whether the protozoan parasite Entamoeba histolytica had monoADP-ribosyl transferase activity. Reactions were initiated using ameba-free medium as the source of both enzyme and ADP-ribosylation substrate(s) and [32P]NAD+ as source of ADP-ribose. Proteins were analyzed by electrophoresis, and [32P]-labeled proteins were detected by autoradiography.