Characterization of Lanthanide Ions Binding Sites in the Cell Wall ofPseudomonas aeruginosa

2000 ◽  
Vol 34 (4) ◽  
pp. 610-615 ◽  
Author(s):  
Anne-Claire Texier ◽  
Yves Andrès ◽  
Myriam Illemassene ◽  
Pierre LE CLOIREC
Keyword(s):  
Cell Wall ◽  
Binding Sites ◽  
Lanthanide Ions

Ion behavior in plant cell walls. I. Characterization of the Sphagnum russowii cell wall ion exchanger

1989 ◽  
Vol 67 (2) ◽  
pp. 451-459 ◽  
Author(s):  
Conrad Richter ◽  
Jack Dainty
Keyword(s):  
Cell Wall ◽  
Cation Exchange ◽  
Binding Sites ◽  
Cell Walls ◽  
Weak Acid ◽  
Wall Material ◽  
Plant Cell Walls ◽  
Donnan Free Space ◽  
Donnan Model

The ion-exchange properties of Sphagnum russowii cell wall material were studied in the context of the Donnan weak acid model. Titrations in the presence of Na+, Ca2+, or La3+ revealed two classes of weak acid binding sites, one with a low pK between 2 and 4 and the other with a high pK > 5. The total cation-exchange capacities of the low and high pK species were 1071 and 545 μequiv./g dry wt. wall material, respectively, and were related to the uronic, amino, and phenolic acid contents of the walls. Differences in pK estimates obtained in the presence of the different cations (pKNa > pKCa > pKLa) could not be explained by our semiarbitrary choice (1 mL/dry wt. wall material), for the effective volume (Donnan free space) bathing the exchange sites. It was concluded that valence-dependent reductions in cation activities in the wall phase are an important contributor to the differences in the pK estimates. Key words: cation exchange, cell wall, titration, Donnan model, weak acid.

Characterization of Thromboxane A2/Prostaglandin H2 Receptors in Porcine Coronary Artery -The Inhibitory Effect of a Novel Dibenzoxepin Derivative, KW-3635

1992 ◽  
Vol 67 (05) ◽  
pp. 582-584 ◽  
Author(s):  
Ichiro Miki ◽  
Akio Ishii
Keyword(s):  
Coronary Artery ◽  
Binding Sites ◽  
Thromboxane A2 ◽  
Inhibitory Effect ◽  
Scatchard Analysis ◽  
Single Class ◽  
Porcine Coronary Artery ◽  
Equilibrium Binding ◽  
H2 Receptors

SummaryWe characterized the thromboxane A2/prostaglandin H2 receptors in porcine coronary artery. The binding of [3H]SQ 29,548, a thromboxane A2 antagonist, to coronary arterial membranes was saturable and displaceable. Scatchard analysis of equilibrium binding showed a single class of high affinity binding sites with a dissociation constant of 18.5 ±1.0 nM and the maximum binding of 80.7 ± 5.2 fmol/mg protein. [3H]SQ 29,548 binding was concentration-dependently inhibited by thromboxane A2 antagonists such as SQ 29,548, BM13505 and BM13177 or the thromboxane A2 agonists such as U46619 and U44069. KW-3635, a novel dibenzoxepin derivative, concentration-dependently inhibited the [3H]SQ 29,548 binding to thromboxane A2/prosta-glandin H2 receptors in coronary artery with an inhibition constant of 6.0 ± 0.69 nM (mean ± S.E.M.).

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