Typical hydrophobic groups

The subunits of an oligomeric protein typically fold into apparently independent globular conformations and then interact with other subunits. The particular surfaces at which protein subunits interact are similar in nature to the interiors of the individual subunits. These interfaces are closely packed and involve both polar and hydrophobic interactions. Interacting surfaces must therefore possess complementary arrangements of polar and hydrophobic groups. 

In contrast to the typical hydrophobic aromatic model compounds often used, Novotny s group extended the range of potential analytes to include sugars, oligopeptides, steroids, and bile acids [35,37,38]. 

Comparative analysis of known sodium channel blockers has resulted in several somewhat distinct models [88-91]. These models suggest that local anesthetic and anticonvulsant sodium channel blockers share a pharmacophore consisting of a hydrophobic group (typically an aryl ring) separated by 5-6 A from a hydrogen bond acceptor-donor group. 

Surfactant molecules are typically depicted using a stick and ball representation as shown in Fig. 36.16. The stick portion represents the hydrophobic group or tail whereas the ball represents the hydrophilic head group. ... 

Figure 3.2 shows typical cationic softener structures, for example, A,A-distearyl-A,iV-dimethyl ammonium chloride (DSDMAC). Cationic softeners have the best sofmess and are reasonably durable to laundering. They can be applied by exhaustion to all fibres from a high liquor to goods ratio bath and they provide a hydrophobic surface and poor rewetting properties, because their hydrophobic groups are oriented away from the fibre surface They are usually not compatible with anionic products (precipitation of insoluble adducts). 

Fig. 6.2 shows a typical plot of surface tension against the logarithm of concentration for a surfactant solution. Appreciable lowering of surface tension is evident even at low concentrations. As the surfactant concentration is increased, the surface tension continues to decrease as the concentration of surfactant molecules at the surface increases. A concentration is reached, however, when the surface layer becomes saturated with surfactant molecules and no further decrease in surface tension is possible. An alternative means of shielding the hydrophobic portion of the amphiphile from the aqueous environment now occurs as the surfactant molecules form small spherical aggregates or micelles in the bulk of the solution. The hydrophobic groups... 

---