Strong reversibility

Ubenimex, [(2(3),3(R))-3-amino-2-hydroxy-4-phenylbutanoyl]-L-leucine, was isolated as an inhibitor of aminopeptidases, on which it acts as a strong, reversible transition-state analogue inhibitor (293). Analogues of ubenimex have been made and some other aminopeptidase inhibitors, not all of them peptides, have been isolated from streptomycetes (294—296). 

The preorganisation approach (b) involves formation of strong reversible covalent arrangements (boronate esters, imines, ketals) of the monomers... 

In aqueous solution the labile ligands (X") are stepwise replaced by water molecules. Under acidic conditions the hydrolysis reactions are strongly reversible, which gives an equilibrium mixture according to Eq. 1. Much effort has been given to quantify the rate and equilibrium... 

The monobasic acids all show a more marked E.M.P than the corresponding salts. They also lower the surface tension of water. The anions appear therefore to approach nearer to the surface in the presence of H ions than K ions. In KOH the e.m.p. is reversed, the K being less repelled from the surface than the OH. Ammonium salts behave like potassium salts except that ammonia is quite different to the other bases, giving a strong reversed E.M.P. and lowering the surface tension of. water like an organic compound. 

C. Schmeiser, On strongly reverse biased semiconductor diodes, to appear. 

A strong reverse flow is required to bring hot combustion products into contact with fresh fuel-air mixture and provide maximum residence time. 

All of these facts indicate a strong reverse correlation beteen the hydroxyl population on the silica surface and the catalyst activity and termination rate. Possibly these hydroxyls coordinate to the active center and kill or at least retard it. Groeneveld et al. have reported that on barely activated samples, protons from surface hydroxyls later appear in the polymer (5,9). This may be evidence of interference by hydroxyls. Or perhaps the hydroxyls are not directly involved at all, but merely reflect some other important change such as the strain introduced onto the surface by their condensation. Whatever the reason, this relationship is used commercially to control MW and many other important polymer properties. 

When the binding energy of the bond to be broken is considerably lower than that of a C-C single bond such as a C-SR bond, the rate of 3-fragmentation can go up dramatically. This is the reason why the addition of thiyl radicals to the double bonds of the nucleobases is so strongly reversible (Chaps 7.4 and 10.5). 

Thiyl radicals add to C-C double bonds, but this reaction is strongly reversible (Ito and Matsuda 1979, 1981, 1982 Ito 1992, 1995). As a consequence, cis-trans isomerization may occur [reactions (37) and (38)]. 

The intrinsic redox processes according to Fig. 3 are strongly reversible, and battery application is straightforward. 

Solid-state 13C NMR experiments on extended-chain /7-C168H338 have shown the strong reversible thermal disordering of chain ends very clearly.95 The methyl and a-methylene signals are clearly distinguished from those of inner methylenes the respective crystalline (all-trans) signals are at 16.1, 25.7, and 33.6 ppm, while their amorphous (conforma-tionally averaged) counterparts are at 15.5, 24.2, and 31.5 ppm. The relative intensities of the crystalline component are shown in Table 2 for 27 and 87 °C. 

Figure 2.6 Tall obstacles (H/b > 2) Effects of uneven obstacle heights. Note strong reverse and downdraft winds (e.g. Lawson, 1980 [360] Britter and Hunt, 1979 [78]).

Another chromophore, namely oxazolopyridocarbazole (OPC) (Figure 49d), related to the ellipticine series, is a strong, reversible intercalator with no major preference for any DNA sequence [129]. This, upon conjugation at the 5 -ends of TFOs, showed a higher stabilization of both Y RY and R-RY motifs, with the target being the HIV-1 U3 (human immunodeficiency virus type 1, gene... 

Preliminary adsorption experiments revealed that the adsorption of FA on hematite surfaces is of the high affinity type. Electrophoretic mobility data (Figure 5(b)) indicate that adsorption of fulvic acid on hematite is not only a consequence of electrostatic interaction between polyanions and positive surface sites, but depends on specific chemical interactions between surface iron (=Fe) and carboxyl (-COO ) groups as well. If electrostatic interaction were the sole driving force for adsorption, the mobility would be expected to be reduced to zero as the FA concentration increases, and would remain at zero as the concentration of FA is further increased. The strong reversal in mobility observed arises from the chemical interaction in addition to the electrostatic force. Consequently, the mobility data are in accord with the observed stability ratio, where at (FA)< 1 x 10 g/l the stability results from net repulsions of positive surfaces, and at (FA)> 1 x 10 g/l the stability arises from repulsion between negative surfaces. Similar conclusions can be drawn with respect to the driving forces for HA adsorption on hematite particles. 

The consequence of a positive cooperativity is that a structural tightening occurs in the bound state with a benefit in enthalpy and a smaller cost in entropy. By studying the unusually strong reversible binding of biotin by avidin = 10 mold) and streptavidin 10 mold), Houk... 

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