Hydrophylic moiety

The same correlation has been measured for five more compounds whose kdiss values (measured in pure water) differ by five orders of magnitudes (Figure 9). The slope of the lines vary with the structure of the compound. Compounds which have a hydrophylic moiety (SO3 ) or polarizable substituent (Br) in ortho position with the dissociating proton (2-naphthol-3,6-disulfonate and Bromocresol Green) are somewhat less affected by water activity than compounds where a hydrophylic moiety is in a more remote position (2-naphthol-6-sulfonate) or no hydrophylic substitution at all (p-naphthol). 

The reduced activity coefficient in the site is sometimes mixed with the hydrophylic moieties. It is of importance to point out that hydrophylic moieties are those that are responsible for the lowering of astrong interaction with the water molecules that arrests them in a tight hydration shell. In the cases listed above we noted low a(H2o) values at sites with high association constant (KA = 106 - 107M-1) for highly sulfonated compounds. Thus, it seems to me that hydrophobic interactions might be better discussed in terms of surface tension (Me-... 

Membrane proteins have a profound influence on the thermotropic properties of lipid bilayers. Moreover, the effects of intrinsic (or integral) proteins are very different from those of extrinsic (or peripheral) proteins, reflecting their different modes of interaction, respectively, from the hydrophobic and hydrophyllic moieties of lipids. Some proteins can also influence, even at very low proteindipid ratios, the lamellar to inverted hexagonal transitions of certain lipids. 

The increase of the concentration of NaCl produces a decrease in the proportion of [RA BH with the consequent increase of Bit and CP in the bulk phase. The incorporation of small ions (having higher mobility than the organic ones) in the PE environment would contribute to keep the level of hydration. However, a dramatic drop of viscosity is produced as depicted in Fig. 15. It should be noted that polymetacrylates, having a hydrophobic backbone without other hydrophylic moieties than carboxylic groups are particularly susceptive to the saline effect. 

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