title: Comparison of the vacuolar membrane ATPase of Neurospora crassa with the mitochondrial and plasma membrane ATPases.
abstract: The vacuolar membrane ATPase of Neurospora crassa closely resembles the mitochondrial ATPase in its substrate specificity, substrate affinity, and sensitivity to the inhibitor N,N'-dicyclohexylcarbodiimide. Three different mutants with altered mitochondrial ATPase activity, exhibited as 1) resistance to N,N'-dicyclohexylcarbodiimide, 2) enhanced sensitivity to N,N'-dicyclohexylcarbodiimide, and 3) very low specific activity, were found to be unaltered in the vacuolar membrane ATPase. The vacuolar membrane ATPase was similar to the mitochondrial ATPase and approximately 10-fold more sensitive than the plasma membrane ATPase in its sensitivity to the inhibitors 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, 2',3'-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate, and 5'-adenylylimidodiphosphate. By contrast, the vacuolar ATPase resembled the plasma membrane ATPase in its response to quercetin (both 10-fold more sensitive than the mitochondrial ATPase); it was unique in its sensitivity to KNO3. A N,N'-dicyclohexylcarbodiimide-binding protein, migrating between molecular weight markers of 14,400 and 21,500, was identified as a putative component of the vacuolar membrane ATPase. Taken together, these findings support the argument that the vacuolar membrane ATPase is a distinct enzyme, more like the mitochondrial F0F1 ATPase than the plasma membrane ATPase.
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D009154:Mutation; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000201:enzymology*; D013347:Subcellular Fractions / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D000266:Adenylyl Imidodiphosphate; D004024:Dicyclohexylcarbodiimide; D000251:Adenosine Triphosphatases; D009327:4-Chloro-7-nitrobenzofurazan