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Karlish SJ, Kempner ES. Minimal functional unit for transport and enzyme activities of (Na+ + K+)-ATPase as determined by radiation inactivation. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 776:288-98. [PMID: 6089887 DOI: 10.1016/0005-2736(84)90218-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Frozen aqueous suspensions of partially purified membrane-bound renal (Na+ + K+)-ATPase have been irradiated at -135 degrees C with high-energy electrons. (Na+ + K+)-ATPase and K+-phosphatase activities are inactivated exponentially with apparent target sizes of 184 +/- 4 kDa and 125 +/- 3 kDa, respectively. These values are significantly lower then found previously from irradiation of lyophilized membranes. After reconstitution of irradiated (Na+ + K+)-ATPase into phospholipid vesicles the following transport functions have been measured and target sizes calculated from the exponential inactivation curves: ATP-dependent Na+-K+ exchange, 201 +/- 4 kDa; (ATP + Pi)-activated Rb+-Rb+ exchange, 206 +/- 7 kDa and ATP-independent Rb+-Rb+ exchange, 117 +/- 4 kDa. The apparent size of the alpha-chain, judged by disappearance of Coomassie stain on SDS-gels, lies between 115 and 141 kDa. That for the beta-glycoprotein, though clearly smaller, could not be estimated. We draw the following conclusions: (1) The simplest interpretation of the results is that the minimal functional unit for (Na+ + K+)-ATPase is alpha beta. (2) The inactivation target size for (Na+ + K+)-dependent ATP hydrolysis is the same as for ATP-dependent pumping of Na+ and K+. (3) The target sizes, for K+-phosphatase (125 kDa) and ATP-independent Rb+-Rb+ exchange (117 kDa) are indistinguishable from that of the alpha-chain itself, suggesting that cation binding sites and transport pathways, and the p-nitrophenyl phosphate binding site are located exclusively on the alpha-chain. (4) ATP-dependent activities appear to depend on the integrity of an alpha beta complex.
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53
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Esmann M, Skou JC. Kinetic properties of C12E8-solubilized (Na+ + K+)-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 787:71-80. [PMID: 6326841 DOI: 10.1016/0167-4838(84)90109-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The properties of the rectal gland (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.8) solubilized in octaethyleneglycol dodecylmonoether ( C12E8 ) have been investigated. The kinetic properties of the solubilized enzyme resemble those of the membrane-bound enzyme to a large extent. The main difference is that Km for ATP for the (Na+ + K+)-ATPase is about 30 microM for the solubilized enzyme and about 100 microM for the membrane-bound enzyme. The Na+-form (E1) and the K+-form (E2) can also be distinguished in the solubilized enzyme, as seen from tryptic digestion, the intrinsic fluorescence and eosin fluorescence responses to Na+ and K+. The number of vanadate-binding sites is unchanged upon solubilization, and it is shown that vanadate binding is much more resistant to detergent inactivation than the enzymatic activities. The number of phosphorylation sites on the 95-100% pure supernatant enzyme is about 3.8 nmol/mg, and is equal to the number of vanadate sites. Inactivation of the enzyme by high concentrations of detergent can be shown to be related to the C12E8 /protein ratio, with a weight ratio of about 4 being a threshold for the onset of inactivation at low ionic strength. At high ionic strength, more C12E8 is required both for solubilization and inactivation. It is observed that the commercially available detergent polyoxyethylene 10-lauryl ether is much less deleterious than C12E8 , and its advantages in the assay of detergent-solubilized (Na+ + K+)-ATPase are discussed. The results show that (Na+ + K+)-ATPase can be solubilized in C12E8 in an active form, and that most of the kinetic and conformational properties of the membrane-bound enzyme are conserved upon solubilization. C12E8 -solubilized (Na+ + K+)-ATPase is therefore a good model system for a solubilized membrane protein.
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54
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Chin G, Forgac M. Purification and proteolysis of vesicles containing inside-out and right-side-out oriented reconstituted (Na+, K+)-ATPase. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42983-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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55
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Deth RC, Smart JL, Lynch CJ, Walsh R. Lack of correlation between [3H]ouabain binding and Na-K ATPase inhibition in rat aorta. Eur J Pharmacol 1984; 99:45-55. [PMID: 6327336 DOI: 10.1016/0014-2999(84)90430-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The binding of [3H]ouabain to intact strips of rat aorta was compared with the ability of ouabain to inhibit the uptake of 86Rb by the same preparation. When a cold temperature wash was used to process tissues after binding of [3H]ouabain, a class of relatively high affinity binding sites was found (KD = 1.2 X 10(-7) M). Binding was saturable and sensitive to both ATP depletion and elevated potassium. Elevation of cytoplasmic Ca2+ levels by phenylephrine or c-AMP levels by theophylline and terbutaline had no influence on [3H]ouabain binding. Ouabain inhibition of 86Rb uptake progressed to 60% of the total 86Rb uptake at 2 X 10(-3) from a threshold of about 10(-5) M. Half-maximal inhibition by ouabain occurred at a concentration of 10(-4) M. The disparity between [3H]ouabain binding and inhibition of 86Rb uptake indicates that the high affinity binding site in the rat does not contribute to inhibition of Na-K ATPase function.
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56
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Feinstein DL, Moudrianakis EN. Hydrophobic and ionic effects upon the electrophoretic mobilities of the subunits of coupling factor 1 from mitochondria. Anal Biochem 1984; 136:362-71. [PMID: 6232867 DOI: 10.1016/0003-2697(84)90231-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A sodium dodecyl sulfate (SDS)-urea polyacrylamide gel system was used to investigate certain properties of the subunits of the beef heart mitochondrial ATPase, (native F1, nF1). By examining the affects of urea concentration and acrylamide concentration upon the electrophoretic mobilities of the polypeptides comprising the nF1 enzyme, we have obtained conditions under which all five subunits are simultaneously resolved when the discontinuous buffer system of Laemmli is used (U. K. Laemmli (1970) Nature (London) 277, 680-685). The determination of the apparent molecular weights by analysis of Ferguson plots (K. A. Ferguson (1964) Metabolism 13, 985-1002) revealed that the addition of urea to the SDS gels resulted in a decrease in the apparent molecular weight of the beta subunit. A dramatic increase in the apparent molecular weight of the delta subunit was also brought about by the presence of urea in the SDS gels. In addition, the apparent molecular weight of both the alpha and the beta subunits was dependent upon the acrylamide concentration used, indicating that these subunits contain either areas highly resistant to denaturation by the combined action of urea and SDS, or covalent modifications leading to anomalous electrophoretic mobility. The results of experiments in which urea analogs were used indicate that the interactions of urea with the beta subunit involve the formation of hydrogen bonds between urea and regions of this subunit. On the other hand, the interactions of urea with the delta subunit are primarily of a hydrophobic nature, suggesting that these interactions could involve domains of the delta subunit required for binding of the coupling factor to the mitochondrial membrane.
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57
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Hiatt A, McDonough AA, Edelman IS. Assembly of the (Na+ + K+)-adenosine triphosphatase. Post-translational membrane integration of the alpha subunit. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43400-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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58
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59
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Benga G, Holmes RP. Interactions between components in biological membranes and their implications for membrane function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1984; 43:195-257. [PMID: 6087406 DOI: 10.1016/0079-6107(84)90014-2] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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60
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Soderberg K, Rossi B, Lazdunski M, Louvard D. Characterization of ouabain-resistant mutants of a canine kidney cell line, MDCK. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44174-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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61
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Maezawa S, Hayashi Y, Nakae T, Ishii J, Kameyama K, Takagi T. Determination of molecular weight of membrane proteins by the use of low-angle laser light scattering combined with high-performance gel chromatography in the presence of a non-ionic surfactant. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 747:291-7. [PMID: 6225464 DOI: 10.1016/0167-4838(83)90108-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
An assessment study was carried out to evaluate the performance of the low-angle laser light scattering technique combined with high-performance gel chromatography in the presence of a nonionic surfactant, octaethyleneglycol n-dodecyl ether, precision differential refractometry and ultraviolet photometry. It was found that the combined technique is highly promising as a method for the determination of the molecular weight of a membrane protein solubilized by the surfactant. For trial, molecular weights of the following membrane proteins of Escherichia coli, both solubilized in oligomeric forms, were measured; porin that forms the transmembrane diffusion pore in the outer membrane, and lambda-receptor protein that facilitates the diffusion of maltose-maltodextrins across the outer membrane. The result obtained indicates that both porin and lambda-receptor protein exist as trimers in the surfactant solution.
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62
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Chipman DM, Lev A. Modification of the conformational equilibria in the sodium and potassium dependent adenosinetriphosphatase with glutaraldehyde. Biochemistry 1983; 22:4450-9. [PMID: 6313040 DOI: 10.1021/bi00288a016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Glutaraldehyde treatment of electroplax membrane preparations of Na,K-ATPase leads to irreversible changes in the enzymic behavior of the protein, which are not due to modification of the active site. When the glutaraldehyde treatment is carried out in a medium containing K+ and without Na+, the "K+-modified enzyme" so produced shows the following changes in enzymic properties: The steady-state phosphorylation by ATP and the rate of ATP-ADP exchange are decreased to approximately 40% of control, while Na,K-ATPase activity decreases to approximately 15% of control. Phosphatase activity is decreased very little, but the potassium activation parameters of the reaction are changed, from K0.5 approximately equal to 5 mM and nH = 1.9 in control to K0.5 approximately equal to 0.5 mM and nH = 1 in K+-modified enzyme. KI(app) for nucleotide inhibition of phosphatase activity is increased significantly. Changes in the cation dependence of the ATPase reaction are also observed. All of these effects can be explained by assuming that the cross-linking of surface groups in protein subunits when they are in conformation E2 shifts the intrinsic conformational equilibrium of the enzyme toward E2. We considered the simplest mathematical model for the coupling between K+ binding and the conformational equilibrium, with equivalent potassium sites that must be simultaneously in the same state. If one assumes that the potassium activation of phosphatase activity in the K+-modified enzyme reflects the affinity for K+ of E2, the behavior of the phosphatase activity in the native enzyme can be fit if there are only two potassium sites, whose affinity is 80-fold higher in E2 than in E1, and the equilibrium constant for E2 in equilibrium E1 is about 250. The same sites can explain the activation of dephosphorylation during ATP hydrolysis. Independent of the model chosen, potassium ions must be required for the catalytic action of form E2 and cannot be merely "allosteric activators". The enzyme modified with glutaraldehyde in a medium containing Na+ also has interesting properties, but their rationalization is less straightforward. The Na,K-ATPase activity is inhibited more than the "partial reactions", as in the K+-modified enzyme. We suggest that this is a generally expected result of modifications of the enzyme.
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63
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Abstract
Membrane-bound (Na+, K+)ATPase from avian nasal salt glands was exposed to limited papain digestion. Such treatment results in the selective removal of the beta-subunit rendering the alpha-subunit still membrane-bound and expressing full enzymic activity. With further exposure to papain the alpha-chain becomes fragmented into two major polypeptide components. The fragmented membrane-bound catalytic chain is extremely sensitive to detergent treatment and cannot be solubilized in an active state.
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64
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Periyasamy SM, Huang WH, Askari A. Subunit associations of (Na+ + K+)-dependent adenosine triphosphatase. Chemical cross-linking studies. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44580-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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65
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Jensen J, Ottolenghi P. ATP binding to solubilized (Na+ + K+)-ATPase. The abolition of subunit-subunit interaction and the maximum weight of the nucleotide-binding unit. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 731:282-9. [PMID: 6303418 DOI: 10.1016/0005-2736(83)90020-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Membrane-bound (Na+ + K+)-ATPase from pig kidney outer medulla shows apparent heterogeneity in its ATP-binding site population when assays are carried out in the presence of K+. This finding has been interpreted as being due to interaction between (at least) two subunits, each containing an ATP-binding site. Treating the membrane-bound enzyme with the detergent, C12E8, has been shown to solubilize enzymatically active alpha beta-protomers. We show that in the dissolved enzyme all ATP-binding sites in the population are identical both in the absence and in the presence of K+, which would be consistent with an abolition of identical both in the absence and in the presence of K+, which would be consistent with an abolition of subunit-subunit interaction. This supports previous suggestions that enzyme solubilized by C12E8 is monomeric and that the membrane-bound enzyme is not. Differential extraction of enzyme-containing membranes with C12E8 yielded preparations with an ATP-binding capacity of up to 5.8 nmol per mg protein, measured by the method of Lowry et al. (Lowry, O.H., Rosebrough, N.J., Farr, A.L. and Randall, R.J. (1951) J. Biol. Chem. 193, 265-275), with bovine serum albumin as standard. Evidence is presented that makes it likely that preparations with an ATP-binding capacity of 7.5 nmol per mg protein (as determined by the above-mentioned assay) will be obtainable. This corresponds to an alpha beta-protomer molecular weight of 133 000 which approximates closely to the minimum value found in the literature for an alpha beta-protomer (i.e., 126 000).
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66
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Sharkey RG. Lactoperoxidase-catalyzed iodination of sodium and potassium ion-activated adenosine triphosphatase in the Madin-Darby canine kidney epithelial cell line and canine renal membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 730:327-41. [PMID: 6303410 DOI: 10.1016/0005-2736(83)90350-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Experiments are described in which the large chain of (Na+ + K+)-ATPase is labeled by lactoperoxidase-catalyzed iodination either at its extracytoplasmic surface exclusively or at both its extracytoplasmic and its cytoplasmic surfaces simultaneously. The former was accomplished by labeling intact cells of the Madin-Darby canine kidney line, and the latter by labeling open membrane vesicles, also from canine kidney. A comparison of the specific radioactivities for the large chain from the open membranes and the large chain from the Madin-Darby canine kidney cells reveals that the former was labeled approximately 5-fold more extensively. This indicates that the large chain of (Na+ + K+)-ATPase is situated in the membrane such that more of its mass protrudes into the cytoplasm than into the extracytoplasmic environment.
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67
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Gupte SS, Lane LK. Reaction of (Na,K)-ATPase with fluorescent maleimide derivatives. Probes for studying ATP site(s) function. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32529-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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68
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Askari A, Huang WH, McCormick PW. (Na+ + K+)-dependent adenosine triphosphatase. Regulation of inorganic phosphate, magnesium ion, and calcium ion interactions with the enzyme by ouabain. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32682-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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69
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Collins JH, Zot AS, Ball WJ, Lane LK, Schwartz A. Tryptic digest of the alpha subunit of lamb kidney (Na+ + K+)-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 742:358-65. [PMID: 6297590 DOI: 10.1016/0167-4838(83)90322-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The Mr approximately equal to 100 000 alpha subunit was prepared from highly purified lamb kidney (Na+ + K+)-ATPase. Its N-terminal sequence is Gly-Arg-Asx-Lys-Tyr-Glu. The alpha subunit was S-carboxymethylated, succinylated, and cleaved at its 40 arginine residues with trypsin. Four major, well-differentiated peptide fractions (A to D) were obtained by chromatography of the digest on a Sephadex G-50 column. Fraction A eluted at the void volume of the column and contained aggregated, very hydrophobic peptides, possibly from regions of alpha that are buried within the membrane lipid bilayer in the native enzyme. Fractions B to D, which together accounted for about 75% of the total protein, contained water-soluble peptides. To test the feasibility of using antibodies to identify and purify specific peptides of alpha subunit, studies were carried out using antibodies to native (Na+ + K+)-ATPase. Carboxymethylation and succinylation did not significantly decrease total antibody binding to alpha subunit, although the affinity of the anti-(Na+ + K+)-ATPase antibodies for alpha subunit was reduced by about 50%. The tryptic peptides of alpha subunit also retain significant immunochemical reactivity. Fractions A, B and C (but not D) of the digest all bind antibodies. To characterize further the tryptic digest, 16 peptides from fraction D were isolated and sequence studies on these were carried out.
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70
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Ottolenghi P, Jensen J. The K+-induced apparent heterogeneity of high-affinity nucleotide-binding sites in (Na+ + K+)-ATPase can only be due to the oligomeric structure of the enzyme. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 727:89-100. [PMID: 6297576 DOI: 10.1016/0005-2736(83)90372-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
K+ induces an apparent heterogeneity among an otherwise homogeneous population of nucleotide-binding sites in (Na+ + K+)-ATPase preparations from pig kidney. With the help of ouabain we show that this heterogeneity cannot be due to a mixture of different and independent sites and conclude that each enzyme molecule must contain two nucleotide site-containing units that show interaction. Na+ induces an apparent heterogeneity among an otherwise homogeneous population of ouabain-binding sites. The argument is, therefore, extended to include one ouabain site on each of the structural units that bind nucleotide. All these structural units are shown to hydrolyse substrate at identical rates. Using the presently available molecular weight data, it is concluded that the enzyme is composed of two subunits each possessing one nucleotide-binding site, one ouabain-binding site, one alpha-peptide and the capacity for hydrolysing ATP and p-nitrophenyl phosphate.
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71
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Structural Aspects of Na.K-ATPase. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0070-2161(08)60551-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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72
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73
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Ligand Interactions with the Substrate Site of Na,K-ATPase: Nucleotides, Vanadate, and Phosphorylation. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0070-2161(08)60581-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
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74
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Peterson GL, Churchill L, Fisher JA, Hokin LE. Structure and biosynthesis of (Na,K)-ATPase in developing brine shrimp nauplii. Ann N Y Acad Sci 1982; 402:185-206. [PMID: 6301330 DOI: 10.1111/j.1749-6632.1982.tb25742.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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75
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Jørgensen PL. Mechanism of the Na+, K+ pump. Protein structure and conformations of the pure (Na+ +K+)-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 694:27-68. [PMID: 6289898 DOI: 10.1016/0304-4157(82)90013-2] [Citation(s) in RCA: 443] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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76
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Munakata H, Schmid K, Collins JH, Zot AS, Lane LK, Schwartz A. The alpha and beta subunits of lamb kidney Na,K-ATPase are both glycoproteins. Biochem Biophys Res Commun 1982; 107:229-31. [PMID: 6289820 DOI: 10.1016/0006-291x(82)91693-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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77
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Peterson GL, Churchill L, Fisher JA, Hokin LE. Structural and biosynthetic studies on the two molecular forms of the (Na+ + K+)-activated adenosine triphosphatase large subunit in Artemia salina Nauplii. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1982; 221:295-308. [PMID: 6286840 DOI: 10.1002/jez.1402210305] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The large subunit of (Na+ + K+)-activated ATPase from brine shrimp, Artemia salina, migrates as two bands in sodium dodecyl sulfate-polyacrylamide gels. The slower migrating band, as observed in neutral or alkaline gel systems, is designated alpha 1 and the faster, alpha 2. Structural and biosynthetic studies have been performed to determine if these two bands represent independent molecular forms or precursor products. Peptide mapping of partial proteolytic digests of alpha 1 and alpha 2 showed no distinguishable difference between them whereas this technique produced very distinct differences in the large subunit derived from three different species. The two large subunit bands also behaved identically when cross linked with cupric phenanthroline either in the presence or absence of digitonin, whereas other proteins in these preparations were unaffected. The peptide mapping and cross-linking experiments demonstrate that alpha 1 and alpha 2 have identical or nearly identical primary and probably higher order structure. Their different mobilities may be due to post-translational modification leading, for example, to different oligosaccharide composition. During development of the brine shrimp nauplius, alpha 1 increases in relative abundance while alpha 2 decreases. NaH14CO3 incorporation and pulse-chase experiments indicate that alpha 1 and alpha 2, as well as the small subunit of the brine shrimp (Na+ + K+)-activated ATPase, are synthesized at the same time during development and that all changes in the rates of synthesis of these subunits occur at the same time. The apparent rates of degradation of the subunits are also similar. These results are inconsistent with a precursor-product relationship between alpha 1 and alpha 2.
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78
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Mayrand RR, Fullerton DS, Ahmed K. A simple method for the purification of rat brain Na+,K+-adenosine triphosphatase (ATPase). JOURNAL OF PHARMACOLOGICAL METHODS 1982; 7:279-88. [PMID: 6289010 DOI: 10.1016/0160-5402(82)90081-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Several methods of purification of Na+,K+-adenosine triphosphatase (ATPase) have been previously described for a wide variety of tissues. In general, highest activity preparations have necessitated large amounts of tissue and many purification steps. This article describes a technique that allows partial purification of Na+,K+-ATPase from as few as 15 rat brains and should be of interest to investigators of the pharmacology of this particular enzyme system. In this modified version of the Jorgensen procedure (Biochim Biophys Acta 356:36--52, 1974) we purified the Na+,K+-ATPase from 15--90 rat brains, and obtained enzyme preparations with a mean specific activity of 552 +/- 37.6 mumol Pi/mg of protein/hr (95.5% ouabain sensitive). This "purified" enzyme had an activity ratio (Mg2+ + Na+ + K+)/(Mg2+ + Na+) of 47.4 +/- 12.3 SEM, compared to 3.29 +/- 0.17 SEM for the untreated microsomes. Ouabain inhibited the "purified" enzyme with an I50 of 6 X 10(-9) M. Ouabain binding (644 pmol/mg of protein) yielded a turnover number of 13,700 min-1. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis of the enzyme revealed predominantly the alpha and beta subunits with some minor contaminant bands. Previous methods of purification of rat brain Na+,K+-ATPase have employed sodium deoxycholate and high concentrations of NaI; the reported specific activity obtained was generally 150--350 mumol Pi/mg of protein/hr. We have employed higher SDS concentrations than in Jorgensen's technique for rabbit kidney but the procedure is simpler because sucrose gradients are not used. Final wash steps also include 10--20% glycerol in the media. These modifications have yielded Na+,K+-ATPase of significantly higher specific activity than previously reported for rat brain.
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79
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Craig WS. Determination of the distribution of sodium and potassium ion activated adenosinetriphosphatase among the various oligomers formed in solutions of nonionic detergents. Biochemistry 1982; 21:2667-74. [PMID: 6284206 DOI: 10.1021/bi00540a014] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Sodium and potassium ion activated adenosinetriphosphatase [(Na+ + K+)-ATPase] can be dispersed from the membrane-bound state, with the stable retention of the capacity to display (Na+ + K+)-ATPase activity, by treatment with solutions of a homogeneous, nonionic detergent, octaethylene glycol dodecyl ether. The dispersed enzyme is incapable of turnover, however, in solutions where the free detergent concentration is above the critical micelle concentration. Treatment of solutions of this enzyme with the crosslinking reagent glutaraldehyde results in the quantitative, covalent coupling of the alpha-and beta-polypeptides. The various covalent products formed, when visualized on sodium dodecyl sulfate-polyacrylamide gels, are integral oligomers of the asymmetric unit (alpha beta) of the enzyme. The noncovalent oligomers from which these products are derived can be separated on sucrose gradients based on differences in their respective sedimentation coefficients, but these sedimentation coefficients are highly dependent on the concentration of detergent in the gradient. Furthermore, the cross-linking assay reveals that changes in the aggregation state of the enzyme occur as detergent:protein ratios are varied or when the enzyme is added to the ATPase assay. These observations suggest that earlier conclusions about the oligomers of this enzyme present in detergent solution were significantly in error.
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80
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Goffeau A, Slayman CW. The proton-translocating ATPase of the fungal plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 639:197-223. [PMID: 6461354 DOI: 10.1016/0304-4173(81)90010-0] [Citation(s) in RCA: 382] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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81
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Schuurmans Stekhoven FM, Swarts HG, De Pont JJ, Bonting SL. Studies on (Na+ + K+)-activated ATPase. XLV. Magnesium induces two low-affinity non-phosphorylating nucleotide binding sites per molecule. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 649:533-40. [PMID: 6274401 DOI: 10.1016/0005-2736(81)90157-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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82
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Freytag JW, Reynolds JA. Polypeptide molecular weights of the (Na+,K+)-ATPase from porcine kidney medulla. Biochemistry 1981; 20:7211-4. [PMID: 6274391 DOI: 10.1021/bi00528a024] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The molecular weights of the polypeptide chains from (Na+,K+)-ATPase of porcine kidney medulla have been determined by analytical sedimentation equilibrium. The alpha-subunit molecular weight is 93 900, and the beta subunit is a glycoprotein with a polypeptide molecular weight of 32 300 (41 400 including protein and carbohydrate). Amino acid and carbohydrate compositions are presented together with related properties (i.e., partial specific volumes, extinction coefficients, and hydrophobic/hydrophilic amino acid content).
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83
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Bowman B, Blasco F, Slayman C. Purification and characterization of the plasma membrane ATPase of Neurospora crassa. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43277-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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84
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Richards DE, Ellory JC, Glynn IM. Radiation inactivation of (Na+ + K+)-ATPase. A small target size for the K+-occluding mechanism. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 648:284-6. [PMID: 6272854 DOI: 10.1016/0005-2736(81)90045-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Radiation inactivation of partially purified (Na+ + K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) from pig kidney outer medulla shows that the target size for Rb+ occlusion by the enzyme (in the absence of phosphorylation) is much smaller than the target size for p-nitrophenyl phosphatase activity, which is itself smaller than the reported target size for (Na+ + K+)-ATPase activity.
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85
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The reaction of sulfhydryl groups of sodium and potassium ion-activated adenosine triphosphatase with N-ethylmaleimide. The relationship between ligand-dependent alterations of nucleophilicity and enzymatic conformational states. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68794-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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86
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Abstract
A small group of closely related proteins is responsible for all active transport in animal cells, and inorganic cations are the only substances transported by these enzymes. They share a common kinetic mechanism in which two fundamental conformations participate, each receiving and dispatching substrates from its unique side of the membrane. During transport, the cations must pass through their enzyme to cross the membrane and intense interest is currently focused on the possibility that the path which they follow lies within the interface between two discrete subunits in a dimeric structure. Although 'half-of-sites' behaviour, consistent with this hypothesis, has been reported, it is now known that systematic errors were responsible for this mistaken conclusion. The number of protomers which comprise a functional unit of active transport has not been determined.
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87
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Brotherus JR, Møller JV, Jørgensen PL. Soluble and active renal Na, K-ATPase with maximum protein molecular mass 170,000 +/- 9,000 daltons; formation of larger units by secondary aggregation. Biochem Biophys Res Commun 1981; 100:146-54. [PMID: 6266398 DOI: 10.1016/s0006-291x(81)80075-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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88
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Campbell K, MacLennan D. Purification and characterization of the 53,000-dalton glycoprotein from the sarcoplasmic reticulum. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69481-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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89
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Abstract
Proteins which traverse membranes tend to have a dimeric structure in which the dimer is arranged asymmetrically across the membrane with the axis of symmetry perpendicular to the membrane plane. This general structure is well suited to the function of transporting nutrients across the cell membrane.
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90
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Molecular weight and stoichiometry of the sodium- and potassium-activated adenosine triphosphatase subunits. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69518-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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91
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Peters WH, Swarts HG, de Pont JJ, Schuurmans Stekhoven FM, Bonting SL. (Na/ + K+)ATPase has one functioning phosphorylation site per alpha subunit. Nature 1981; 290:338-9. [PMID: 6259540 DOI: 10.1038/290338a0] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
(Na+ + K+)ATPase contains two different subunits, a catalytic subunit (alpha) and a subunit with uncertain function (beta). The enzyme binds ATP, ouabain and vanadate, and can be phosphorylated by ATP as well as by inorganic phosphate. From the previously reported maximal binding and phosphorylation capacities of 3.5--4.3 nmol P per mg protein (based on Lowry protein determination) and the earlier molecular weight value of approximately 250,000, a molar binding and phosphorylation capacity of 0.87--1.07 mol per mol enzyme was derived. As it is generally agreed that the enzyme molecule contains two alpha subunits or even a multiple of two, it has been suggested that the enzyme operates by means of a so-called "half-of-the-sites mechanism" whereby only of the two alpha subunits can be phosphorylated at any one time. We now present evidence that every alpha subunit can be phosphorylated simultaneously, which rules out the operation of such a mechanism.
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92
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Moczydlowski E, Fortes P. Characterization of 2',3'-O-(2,4,6-trinitrocyclohexadienylidine)adenosine 5'-triphosphate as a fluorescent probe of the ATP site of sodium and potassium transport adenosine triphosphatase. Determination of nucleotide binding stoichiometry and ion-induced changes in affinity for ATP. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69786-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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93
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Peters WH, de Pont JJ, Koppers A, Bonting SL. Studies on (Na+ + K+)-activated ATPase. XLVII. Chemical composition, molecular weight and molar ratio of the subunits of the enzyme from rabbit kidney outer medulla. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 641:55-70. [PMID: 6260183 DOI: 10.1016/0005-2736(81)90568-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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94
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Smith R, Zinn K, Cantley L. A study of the vanadate-trapped state of the (Na,K)-ATPase. Evidence against interacting nucleotide site models. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(18)43471-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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