Characterization of plasma membrane adenosine triphosphatase of Neurospora crassa.
It has been proposed (Slayman, C.L., Long W.S., and Lu, C.Y.-H. (1973) J. Membr. Biol. 14, 305--338) that in Neurospora crassa, a plasma membrane ATPase functions to pump H+ ions out of the cell, thereby generating an electrochemical gradient that can drive transport processes. Using the concanavalin A method of Scarborough (Scarborough G.A. (1975)J. Biol. Chem. 250, 1106--1111), we have prepared plasma membranes of Neurospora and have deomonstrated that they do contain a distinct ATPase activity with the following properties. It has a pH optimum of 6.0, is highly specific for ATP (hydrolyzing other nucleoside triphosphates less than 6% as rapidly), requires Mg2+ at concentrations approximately equimolar to the concentration of ATP, is weakly stimulated by certain monovalent cations (K+ and NH4+) and anions (SCN- and acetate), is inhibited by N,N'-dicyclohexylcarbodiimide, but is not affected by oligomycin or ouabain. The plasma membrane fraction also contains residual mitochondrial contamination, which can be determined quantitatively by assaying oligomycin-sensitive ATP-ase activity, at pH 8.25, and succinic dehydrogenase activity.
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D002413:Cations, Divalent; D002458:Cell Fractionation / Q000379:methods; D002462:Cell Membrane / Q000201:enzymology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008928:Mitochondria / Q000201:enzymology; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000201:enzymology* / Q000648:ultrastructure; D009711:Nucleotides / Q000378:metabolism; D009840:Oligomycins / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
D002413:Cations, Divalent; D009711:Nucleotides; D009840:Oligomycins; D004024:Dicyclohexylcarbodiimide; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium