Sulfate metabolism in Entamoeba histolytica.
Sulfate fluxes and sulfate metabolites in Entamoeba histolytica were characterized employing [35S]sulfate as a marker. Sulfate was taken up both across the plasma membrane and by pinocytosis; in growth medium (sulfate concentration, 1.1 mM) total uptake was 1.5 mumol h-1 (5 x 10(7) cells)-1. The fate of sulfate within the cells was investigated by thin-layer chromatography. Major metabolites (together greater than 3 mumol (5 x 10(7) cells)-1) were monoethyl sulfate and 3-cholesteryl sulfate; both these products were released into the growth medium. As minor components we identified the activated sulfate derivatives, adenosine-5'-phosphosulfate and 3'-phosphoadenosine-5'-phosphosulfate. In addition, up to 10% of the sulfate taken up was incorporated into high-molecular weight material (possibly proteoglycans). We propose that sulfurylation of cholesterol may play a role in controlling membrane sterol content.
Bakker-Grunwald
T
T
Department of Microbiology, University of Osnabrück, Germany.
Geilhorn
B
B
D000250:Adenosine Phosphosulfate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D004748:Entamoeba histolytica / Q000378:metabolism*; D010724:Phosphoadenosine Phosphosulfate / Q000378:metabolism; D010873:Pinocytosis; D013431:Sulfates / Q000378:metabolism*
D002788:Cholesterol Esters; D013431:Sulfates; D010724:Phosphoadenosine Phosphosulfate; D000250:Adenosine Phosphosulfate; C007045:cholesteryl sulfate