Presence of a fructose-2,6-bisphosphate-insensitive pyrophosphate: fructose-6-phosphate phosphotransferase in the anaerobic protozoa Tritrichomonas foetus, Trichomonas vaginalis and Isotricha prostoma.
Extracts of the anaerobic protozoa Tritrichomonas foetus, Trichomonas vaginalis and Isotricha prostoma contained a high activity (0.5-1 mumol min-1 (mg protein)-1) of pyrophosphate:fructose-6-phosphate phosphotransferase (PPi-PFK), but no detectable ATP: fructose-6-phosphate phosphotransferase. PPi-PFK from I. prostoma was purified close to homogeneity by adsorption on phospho-Ultrogel and elution with fructose-1,6-bisphosphate, and subsequent anion-exchange chromatography. The enzyme had an Mr of 95,000 as determined by gel filtration and consisted of subunits of Mr 48,000. PPi-PFK from I. prostoma and from T. foetus displayed hyperbolic kinetics with respect to their substrates and were not affected by fructose-2,6-bisphosphate. In sharp contrast with what has been found in other eukaryotes, no evidence could be found for the presence of fructose-2,6-bisphosphate in the two trichomonads, in I. prostoma and in Entamoeba histolytica.
Mertens
E
E
Laboratory of Physiological Chemistry, Catholic University of Louvain, Belgium.
Van Schaftingen
E
E
Müller
M
M
D000818:Animals; D002852:Chromatography, Ion Exchange; D016798:Ciliophora / Q000201:enzymology*; D005635:Fructosediphosphates / Q000494:pharmacology; D005636:Fructosephosphates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010770:Phosphotransferases / Q000302:isolation & purification / Q000378:metabolism*; D014244:Trichomonas / Q000201:enzymology*; D014318:Tritrichomonas / Q000201:enzymology*
D005635:Fructosediphosphates; D005636:Fructosephosphates; C027618:fructose-6-phosphate; C027652:fructose 2,6-diphosphate; D010770:Phosphotransferases; C022502:pyrophosphate-fructose 6-phosphate 1-phosphotransferase