Hydrophobic groups, bulky

Thus complete intercalation of the aromatic PAH between the bases of DNA, in the manner described above for flat molecule such as proflavine, did not seem to be a likely mechanism for the carcinogenic action of these compounds. Since alkylation and intercalation are not simultaneously possible for steric reasons, and since one molecule is wedge-shaped and the other is flatter, it was considered more likely that the action of these compounds arose from their alkylating ability they could alkylate a base of DNA and then, since the bulky aromatic hydrophobic group would possibly not remain protruding into the hydrophilic environment, it is possible that the aromatic PAH group could then lie in one of the grooves of DNA. 

Reversible, non-competitive inhibition of polymerase is also afforded by a series of N-benzoyl pyrrolidines. Substitution on the benzoyl moiety with a para-trifluoromethyl group is optimal in this series. Bulky, hydrophobic groups at the 2-position of the pyrrolidine ring increase activity, and the 5-position tolerates a wide range of substituents, indicative of a solvent exposed portion of the inhibitor. Compound (+)-38, containing a 2-thienyl moiety at the 5-position, has an IC50 of 190 nM in the enzyme assay while its enantiomer is almost 100-fold less active [83]. 

PEGs also showed enhanced stability similar to that of ph-PEG. PEG containing hydroquinone substitutions showed a decrease in critical chain length but again not as drastically as the naph-PEG because the bulky hydrophobic group on the hydroquinone is in the middle of the chain while that of the 1-naphthol is on the end of the chain. Thus the effects of hydrophobic interactions have been shown to be a universal stabilizing factor in interpolymer complexation. 

Another characteristic property of many biopolymers (proteins, modified starch, chitosan, etc.) which is useful for the encapsulation of bioactive molecules is their ability to adsorb at the oil-water interface and to form adsorbed layers that are capable of stabilizing oil-in-water (OAV) emulsions against coalescence (see Table 2.2). It is worthwhile to note here that the formation of an emulsion is one of the key steps in the encapsulation of hydrophobic nutraceuticals by the most common technique used nowadays in the food industry (spray-drying). The adsorption of amphiphilic biopolymers at the oil-water interface involves the attachment of their hydrophobic groups to the surface of the oil phase (or even their slight penetration into it), whilst their hydrophilic parts protrude into the aqueous phase providing a bulky interfacial layer. 

Portions of the statins (shown In blue) clearly resemble HMG-CoA. However, the bulky hydrophobic groups of the inhibitors differ from the CoA moiety of the substrate. 

In the example shown in Figure 1.1.1, the water solubilities and the octanol-water partition coefficients of benzene, chlorobenzene, and toluene are related directly through the QPPR Kov/ =f(Sw). In this case, only one property, the water solubility, is used as the predictor variable. Chlorobenzene, the query, is considered similar to toluene and benzene because it contains one aromatic ring. The chlorine substituent is hydrophobic and bulky, similar to the methyl group of toluene. If the range of compounds is expanded to n other compounds, the applicability of the QPPR is expanded to all compounds similar to the set of n compounds included in the training set. 

The modified protein should be easy to purify from the reaction mixture, and there must be some way in which to quantitate the extent of modification. Most importantly, the modified protein should be soluble in physiological solutions, and retain full biological activity in such solutions. This requirement usually specifies that modification does not change the overall charge or the conformation of the protein, involve critical residues, or introduce bulky or hydrophobic groups. 

If a bulky hydrophobic group is introduced at the 5-position of isophthalic acid, a cyclic hexamer (rosette) is generated. In the crystal structure of trimesic acid, the voids are filled through interpenetration of two honeycomb... 

Acetylation of wood (A) was done in neat acetic anhydride at 120°C for 10 h, followed by leaching 10 h in boiling water and oven-drying overnight. Acetylation leads to the structure of pattern (A-4) + (B-6), hydrophilic hydroxyl groups being substituted with hydrophobic and bulky acetyl groups. 

Like many HDAC inhibitors, TSA acts by using a bulky hydrophobic group to block the HDAC pocket and a polar region to interact with the HDAC active site zinc atom (Fig. 3)... 

CDs Chiral recognition is based on inclusion of the bulky hydrophobic group of the analyte into the hydrophobic cavity of the CD and on lateral interactions of the hydroxyl groups, such as hydrogen bonds and dipole-dipole interactions, with the analyte. Carboxymethylated P-CD, heptakis- 0-methyl- P-CD, hy dr oxy ethyl- P- CD, mono(6-P-aminoethylamino-6-deoxy)-P-CD, and mono(6-amino-6-deoxy)-P-CD. Acebutolol, acenocoumarol, carnitine, cathinone, ephedrine, epinephrine, glutethimide, ketotifen, thioridazine, etc. 

The surface pressures at the oil and water sides of the interface depend on the interactions of the hydrophobic and hydrophilic potions of the surfactant molecule at both sides, respectively. If the hydrophobic groups are bulky in nature relative to the hydrophihc groups, then for a flat film such hydrophobic groups tend to crowd so as to form a higher surface pressure at the oil side of the interface this results in bending and expansion at the oil side, forming a W/O microemulsion. 

An example of a surfactant with bulky hydrophobic groups is Aerosol OT (dioctyl sulphosuccinate). If the hydrophilic groups are bulky, as is the case with ethoxylated surfactants containing more than five ethylene oxide units, crowding will occur at the water side of the interface and this will produce an O/W microemulsion. 

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