Ligands derived from C-aryl substituted derivatives of cyclen: formation of kinetically unstable complexes with lanthanide(III) ions by Edlin, C, Faulkner, S, Parker, D, Wilkinson, M, Woods, M, Lin, J, Lasri, E, Neth, F, Port, M

“…Octadentate ligands derived from these C-substituted macrocycles form relatively labile eight-coordinate complexes, which dissociate when challenged with EDTA in aqueous solution at pH 5.5, suggesting their use in metal-transport processes rather than for applications in vivo.…”

Relaxometric and luminescence behaviour of triaquahexaazamacrocyclic complexes, the gadolinium complex displaying a high relaxivity with a pronounced pH dependence by Hall, J, Haner, R, Aime, S, Botta, M, Faulkner, S, Parker, D, de Sousa, A

“…Measurements of the luminescence lifetime of a very similar complex, [YbL2]3+, in H2O and D2O were used to confirm that the complex possesses three bound waters at pH 5.5, but above pH 11 there are no bound OH groups in the putative di-oxo-bridged dimer.…”

Influence of pH on the conformation and stability of mismatch base-pairs in DNA. by Brown, T, Leonard, G, Booth, E, Kneale, G

“…In one case, a duplex containing two A.C mismatches is more stable than the native sequence below pH 5.5. The G.A mismatch displays conformational flexibility, with a protonated G(syn).A(anti) base-pair occurring in certain base stacking environments but not in others. …”

Surfactin structures at interfaces and in solution: the effect of pH and cations. by Shen, H, Lin, T, Thomas, R, Taylor, D, Penfold, J

“…At high pH surfactin forms micellar structures with low aggregation numbers, but at low pH values the bulk phase structure becomes rod-like at pH 6.5 and lamellar at pH 5.5. The addition of cations in the subphase tends to neutralize the two acidic groups of the peptide ring and the neutralization seems to be more complete for divalent cations than for monovalent cations.…”

P NMR Observations on the Effect of the External pH on the Intracellular pH Values in Plant Cell Suspension Cultures. by Fox, G, Ratcliffe, G

“…In contrast to earlier studies the cytoplasmic pH was independent of the external pH over the range 5.5 to 8.0 and it was only below pH 5.5 that the cytoplasmic pH varied, falling at a rate of 0.12 pH unit per external unit. …”

DIRECT ELECTROCHEMISTRY IN THE CHARACTERIZATION OF REDOX PROTEINS - NOVEL PROPERTIES OF AZOTOBACTER 7FE FERREDOXIN by Armstrong, F, George, S, Thomson, A, Yates, M

“…The [3Fe-4S] cluster exhibits pH dependent E 1 2 values (30°C); E 1 2 (alkaline) = 460 ± 10 mV vs NHE, -dE 1 2/d(pH) = 55 mV, pK = 7.8. The [4Fe-4S] cluster is characterised by an unusually low reduction potential, -645 ± 10 mV vs NHE, at pH 8.3, with a slight pH dependence, -dE 1 2/d(pH) ∼25 mV over the pH range 8.5-7.0. …”

ERK2 signalling from internalised epidermal growth factor receptor in broken A431 cells. by Xue, L, Lucocq, J

“…Our observation that EGFR tyrosine dephosphorylation is incomplete above pH 5.5 suggests that signalling is initiated in early endosomes.…”

5-(1-propargylamino)-2'-deoxyuridine (UP): a novel thymidine analogue for generating DNA triplexes with increased stability. by Bijapur, J, Keppler, MD, Bergqvist, S, Brown, T, Fox, K

“…The intra-molecular triplex A6-L-T6-L-(UP)5T (L = two octanediol residues) shows a single UV-melting transition which is >20 degrees higher than that of the parent triplex A6-L-T6-L-T6at pH 5.5. Although a single transition is observed at all pHs, the melting temperature (Tm) of the modified oligonucleotide decreases at higher pHs, consistent with the requirement for protonation of the amino group. …”

Polymer supported calix[4]arene-semicarbazone derivative for separation and preconcentration of La(III), Ce(III), Th(IV) and U(VI) by Jain, V, Handa, A, Pandya, R, Shrivastav, P, Agrawal, Y

“…The resin exhibits good separating ability with maximum sorption between pH 2.5-4.5 for Th(IV) and between pH 5.5-7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5-8.5. …”

Acid-induced demineralisation of human enamel as a function of time and pH observed using X-ray and polarised light imaging by Harper, RA, Shelton, RM, James, JD, Salvati, E, Besnard, C, Korsunsky, AM, Landini, G

“…At pH 4.0, there was complete mineral loss in the centre of the demineralised area after the 3-week period and the linear function intercepted the x-axis at ~ pH 5.5, near the critical pH for hydroxyapatite (HAp). …”

Molecular Studies of Membrane Interactions Using Probe Methods by Bashford, L

“…A detailed analysis of the pH dependence of the ATPase, the associated fluorescence response, the uncoupling of the fluorescence response end the passive binding of the probe suggest that one mechanism by which the granules retain their catecholamines is low pH (matrix pH appears to be about pH 5.5). Low pH also provides a suitable chemical environment for the catecholamines which are unstable and readily oxidised at pH values above 7.5. …”

Hydrophobic interactions in proteins by Louis, C

“…With lysozyme the percentage loss of protein from solution at the dip increased sharply over the range pH 5.5 to pH 6.0 where dimerization of the protein is known to occur. …”