Biomaterial Database

Identification and properties of an ATPase in vacuolar membranes of Neurospora crassa. 1982

E J Bowman, and B J Bowman

Using a vacuolar preparation virtually free of contamination by other organelles, we isolated vacuolar membranes and demonstrated that they contain an ATPase. Sucrose density gradient profiles of vacuolar membranes show a single peak of ATPase activity at a density of 1.11 g/cm3. Comparison of this enzyme with the two well-studied proton-pumping ATPases of Neurospora plasma membranes and mitochondria shows that it is clearly distinct. The vacuolar membrane ATPase is insensitive to the inhibitors oligomycin, azide, and vanadate, but sensitive to N,N'-dicyclohexylcarbodiimide (Ki = 2 microM). It has a pH optimum of 7.5, requires a divalent cation (Mg2+ or Mn2+) for activity, and is remarkably unaffected (+/- 20%) by a number of monovalent cations, anions, and buffers. In its substrate affinity (Km for ATP = 0.2 mM), substrate preference (ATP greater than GTP, ITP greater than UTP greater than CTP), and loss of activity with repeated 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid washes, the vacuolar membrane ATPase resembles the F1F0 type of ATPase found in mitochondria and differs from the integral membrane type of ATPase in plasma membranes.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D009491	Neurospora	A genus of ascomycetous fungi, family Sordariaceae, order SORDARIALES, comprising bread molds. They are capable of converting tryptophan to nicotinic acid and are used extensively in genetic and enzyme research. (Dorland, 27th ed)	Neurosporas
D009492	Neurospora crassa	A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.	Chrysonilia crassa
D009940	Organoids	An organization of cells into an organ-like structure. Organoids can be generated in culture, e.g., self-organized three-dimensional tissue structures derived from STEM CELLS (see MICROPHYSIOLOGICAL SYSTEMS). They are also found in certain NEOPLASMS.	Organoid
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
D004024	Dicyclohexylcarbodiimide	A carbodiimide that is used as a chemical intermediate and coupling agent in peptide synthesis. (From Hawley's Condensed Chemical Dictionary, 12th ed)	DCCD
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, Adenosine