Binding hydrophobic character

The binding domain for the hormone, or LBD, is situated in the carboxyl half of the receptor, the final portion of which is critical. For example, the deletion of 12 amino acids in the carboxyl end of the androgen receptor suppresses its capacity to bind hormone (O Malley et al. 1974). The LBD has an amino acid composition that confers upon it a net hydrophobic character, suitable for interacting with organic molecules of low molecular weight, such as steroids. 

Phosphohpase Cy and protein tyrosine phosphatase Syp possess an SH2 domain of class 3. Their substrate binding site has mostly hydrophobic character. The substrate is boimd in a stretched form in a flat pit where contacts are formed to a hydrophobic sequence section of the substrate, including 5—6 amino acids on the C-terminal side of the phosphotyrosine residue. 

Equilibrium constants for the binding between substrates and micelles — Reaction (G) — generally range from 103 to 106 for hydrophobic organic substrates. Furthermore, they are expected to increase as the hydrophobic character of the substrate increases. Figure 8.10b shows that this effect sometimes overshoots optimum solubilization. The figure shows, on a... 

Because of their hydrophobic character the steroid hormones or other nonpolar ligands diffuse through membranes into cells. There they may encounter a variety of binding proteins that affect their access to a receptor.307 311 Some receptors, including glucocorticoid receptors, are found in the cytosol. After a hor-... 

Flavonoids bear different degrees of hydroxylation, polymerization, and methylation that define both specific and nonspecific interactions with membrane lipids. Molecule size, tridimensional structure, and hydrophili-city/hydrophobicity are chemical parameters that determine the nature and extent of flavonoid interactions with lipid bilayers. The hydrophilic character of certain flavonoids and their oligomers endows these molecules with the ability to bind to the polar headgroups of lipids localized at the water-lipid interface of membranes. On the other hand, flavonoids with hydrophobic character can reach and cross the lipid bilayer. In this section, we will discuss current experimental evidences on the consequences of flavonoid interactions with both the surface and the hydrophobic core of the lipid bilayer. 

The hydrophobic character of organic pollutants means that they can be adsorbed by sediments or particles in suspension or bind to DOMs such as humic substances. The hydrophobicity of organic pollutants reduces the probability of finding them free in water. 

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