Das Genauigkeitsma� von Summen, Differenzen, Produkten und Quotienten der Beobachtungsreihen

Fenner, Germano

doi:10.1007/bf01520425

Cited by 34 publications

(13 citation statements)

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“…Calculations were performed using GraphPad Prism version 5.0a for Mac OS X, GraphPad Software, La Jolla California USA, (www.graphpad.com). The standard deviation for the k cat /K m values was calculated according to Fenner [51].…”

Section: Methodsmentioning

confidence: 99%

Functional Mapping of Human Dynamin-1-Like GTPase Domain Based on X-ray Structure Analyses

et al. 2013

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Human dynamin-1-like protein (DNM1L) is a GTP-driven molecular machine that segregates mitochondria and peroxisomes. To obtain insights into its catalytic mechanism, we determined crystal structures of a construct comprising the GTPase domain and the bundle signaling element (BSE) in the nucleotide-free and GTP-analogue-bound states. The GTPase domain of DNM1L is structurally related to that of dynamin and binds the nucleotide 5′-Guanylyl-imidodiphosphate (GMP-PNP) via five highly conserved motifs, whereas the BSE folds into a pocket at the opposite side. Based on these structures, the GTPase center was systematically mapped by alanine mutagenesis and kinetic measurements. Thus, residues essential for the GTPase reaction were characterized, among them Lys38, Ser39 and Ser40 in the phosphate binding loop, Thr59 from switch I, Asp146 and Gly149 from switch II, Lys216 and Asp218 in the G4 element, as well as Asn246 in the G5 element. Also, mutated Glu81 and Glu82 in the unique 16-residue insertion of DNM1L influence the activity significantly. Mutations of Gln34, Ser35, and Asp190 in the predicted assembly interface interfered with dimerization of the GTPase domain induced by a transition state analogue and led to a loss of the lipid-stimulated GTPase activity. Our data point to related catalytic mechanisms of DNM1L and dynamin involving dimerization of their GTPase domains.

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Section: Methodsmentioning

confidence: 99%

Functional Mapping of Human Dynamin-1-Like GTPase Domain Based on X-ray Structure Analyses

et al. 2013

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“…in measurements performed at low ionic strength), the specificity constant ( k cat /K m ) was obtained by dividing the first-order rate constant (determined by linear regression) by the active enzyme concentration present in the reaction mixture. The standard deviation for the k cat / K m values was calculated according to Fenner [19]. The standard errors of the kinetic parameters were below 20 %.…”

Section: Methodsmentioning

confidence: 99%

C-terminal residues of mature human T-lymphotropic virus type 1 protease are critical for dimerization and catalytic activity

Kádas

Boross

Weber

et al. 2008

Biochemical Journal

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HTLV-1 [HTLV (human T-cell lymphotrophic virus) type 1] is associated with a number of human diseases. HTLV-1 protease is essential for virus replication, and similarly to HIV-1 protease, it is a potential target for chemotherapy. The primary sequence of HTLV-1 protease is substantially longer compared with that of HIV-1 protease, and the role of the ten C-terminal residues is controversial. We have expressed C-terminally-truncated forms of HTLV-1 protease with and without N-terminal His tags. Removal of five of the C-terminal residues caused a 4–40-fold decrease in specificity constants, whereas the removal of an additional five C-terminal residues rendered the protease completely inactive. The addition of the N-terminal His tag dramatically decreased the activity of HTLV-1 protease forms. Pull-down experiments carried out with His-tagged forms, gel-filtration experiments and dimerization assays provided the first unequivocal experimental results for the role of the C-terminal residues in dimerization of the enzyme. There is a hydrophobic tunnel on the surface of HTLV-1 protease close to the C-terminal ends that is absent in the HIV-1 protease. This hydrophobic tunnel can accommodate the extra C-terminal residues of HTLV-1 protease, which was predicted to stabilize the dimer of the full-length enzyme and provides an alternative target site for protease inhibition.

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“…One dose of the metered aerosol of ipratrop ium bromide (0.02 mg) exerted, in these experiments, an inhibition of 48% of the ACh effect with a half-life of more than 60 min and no cardiovascular effects. The difference between the effects of ipratrop ium bromide and fenoterol hydrobromide was statistically significant; the same is valid for the efficacy of the combination versus the effect of fenoterol hydrobro mide (Newman-Keuls test according to Fenner, 1931], which is as long-lasting as the effect of ipratropium bromide alone, and without side effects on heart rate or blood pressure (table I). The synergism of the bronchospasmolytic effects of fenoterol hydrobromide and ipratropium bromide was more marked in dogs.…”

Section: Resultsmentioning

confidence: 80%

“…In dogs the effect versus control results was tested with the paired t test [Student, 1908]. Secondly, the additive bronchospasmolytic effect of the combination (c) in comparison to the components fenoterol hydrobro mide (a) and ipratropium bromide (b) was proved in guinea pigs with the law of propagation of error (Fenner, 1931], testing the hypothesis a + b -c = 0. In dogs, the same hypothesis was analyzed by the t test for the comparison of a sample mean with the popu lation mean (Fisher, 1926).…”

Section: Methodsmentioning

confidence: 99%

Pharmacological Effects of a Combination of Fenoterol Hydrobromide and Ipratropium Bromide

Traunecker¹,

Muačević²

1986

Respiration

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The bronchospasmolytic and cardiovascular effects of fenoterol hydrobromide and ipratropium bromide alone and in combination were investigated using metered aerosols in guinea pigs and dogs and intravenous injection in dogs. The additive effect of the combination on bronchospasmolysis could be demonstrated. The slight cardiovascular side-effects of fenoterol hydrobromide alone were reduced to an insignificant level with the combination administered as a metered aerosol, but were still present when the combination was administered parenterally. Ipratropium bromide in both forms of administration had no effect on the cardiovascular system

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Das Genauigkeitsma� von Summen, Differenzen, Produkten und Quotienten der Beobachtungsreihen

Cited by 34 publications

References 0 publications

Functional Mapping of Human Dynamin-1-Like GTPase Domain Based on X-ray Structure Analyses

Functional Mapping of Human Dynamin-1-Like GTPase Domain Based on X-ray Structure Analyses

C-terminal residues of mature human T-lymphotropic virus type 1 protease are critical for dimerization and catalytic activity

Pharmacological Effects of a Combination of Fenoterol Hydrobromide and Ipratropium Bromide

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