Inorganic pyrophosphatase of Trichomonas vaginalis.
Trichomonas vaginalis homogenates were found to have an acid inorganic pyrophosphatase activity with a specific activity at pH 4.8 of about 7 nmol min-1 (mg protein)-1. This activity was localized predominantly in hydrolase containing particles, showed structure-bound latency and was tightly membrane-bound. The activity showed no magnesium dependence, a Km of about 2 mM inorganic pyrophosphate, a pH optimum of 5.2 and was inhibited by fluoride at millimolar levels. No evidence was obtained for the existence of a cytosolic magnesium-dependent activity but the existence of a low level of magnesium-independent cytosolic activity cannot be excluded. These observations correlate with the importance of cytosolic inorganic pyrophosphate in the carbohydrate catabolism in T. vaginalis.
Searle
S M
SM
Rockefeller University, New York, NY 10021.
Müller
M
M
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D003600:Cytosol / Q000201:enzymology; D005459:Fluorides / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008247:Lysosomes / Q000201:enzymology; D008274:Magnesium / Q000494:pharmacology; D011755:Pyrophosphatases / Q000378:metabolism*; D014246:Trichomonas vaginalis / Q000201:enzymology*
D000135:Acid Phosphatase; D011755:Pyrophosphatases; D008274:Magnesium; D005459:Fluorides