Relationship between hydrophobicity

Hafkenscheid, T.L. and Tomlinson, E. Relationships between hydrophobic (lipophilic) properties ofbases and their retention in reversed-phase liquid chromatography using aqueous methanol mobile phases. J. Chromatogr. A, 292(2) 305-317, 1984. 

Keshavarz, E. and Nakai, S. 1979. The relationship between hydrophobicity and interfacial tension of proteins. Biochim. Biophys. Acta 576, 269-279. 

Townsend, A.-A. and Nakai, S. 1983. Relationships between hydrophobicity and foaming characteristics of food proteins. J. Food Sci. 48 588-594. 

In Fig. 30, a three-dimensional model is presented in which only the organic phases are shown. Hexagonal plates of MM alternate with pleated sheets of CP. The hydrophobic sides of MM are facing each other and encase the mineral phase. The relationship between hydrophobic bonding and accessible surface area in proteins, and the effect of polar and non-polar side groups on free energy values has recently been discussed246. For informations on hydrophobicity in protein systems see Refs.247-252. ... 

Analysis of the relationship between amino acid properties and protein stability showed that hydrophobicity is the major factor for the stability of proteins during substitution of amino acids in the interior of the protein. The stability of protein mutants is attributed to the number of carbon atoms, which shows the direct relationship between hydrophobicity and stability. 

Schelenz, T, Klunker, J., Bernhardt, T, Schafer, W. and Dost, J. (2001) Relationships between hydrophobicity and algistatic activity of 5-aryl-3H-[l,3,4]oxadiazole-2-thiones. Quant. Struct. -Act. Relat., 20, 291-297. 

Enzymatic hydrolysis of proteins results in changing the molecular mass of the molecules. However, the effects of protein size on the hydrophobic behavior of amino acids are of great importance [132]. There is a meaningful relationship between hydrophobicity (which may affect the surface of the molecule) and functionality of food proteins [11,133] proposed using the term relative surface hydrophobicity. The proteolysis should be carefully limited for improving the functional properties of food proteins [147]. Mild hydrolysis improves functionality of proteins, while extensive hydrolysis depresses it [139,148],... 

Since there seems to be a definite relationship between hydrophobicity and flux decline, this would seem to indicate that there are specific chemical characteristics of the IHSS HA, which cause the observed flux decline. The solubility of the compounds, which is related to molecular size, is most likely responsible for the difference. In fact, the sizes of the NOM fractions are not very different, although large enough for a change in rejection. The hydrophilic fraction is retained less than the FA and HA fractions (see Table 7.34). 

Figure 10. Cartoon of the relationship between hydrophobic association and entropic elastic force development. Above A series of clam-shaped globular protein strung together by elastic bands with an equilibrium between open and hydrophobically associated closed states. Clearly, as the equilibrium shifts toward more closed states, the force, sustained by the interconnecting elastic segments, increases. Below Representation of the p-spiral structure of...

The growth of endotheUal cells (HUVEC) at modified PVC/EVACO surfaces was investigated over a period of seven days and compared to the unmodified surface and to the positive standard Thermanox [130]. After seven days the highest proliferation rate was found at the SO2 plasma treated surface and achieved 103% of that of the positive control. The contact angle of 67° is a sign of a moderate relationship between hydrophobic and hydrophilic groups, which was postulated by Ikada as the optimal condition for ceU attachment and growth [131]. 

FIG. 6 Relationship between hydrophobicity and log cmc of sodium salt of N-lauroyl-L-amino acids 40°C by electroconductivity method. (From Ref. 49.)... 

The relationship between hydrophobic group adherence and interfacial tension impinges on a wide spectrum of biological activities. Only the more important influences can be considered here and then only very briefly. It is convenient to discuss these in two parts, namely the influence of hydrophobic groups on water-structure, and the potential of variation in interfacial tension on the expression of biopolymer conformational change. 

Investigators have found a relationship between hydrophobicity and toxicity in fish (Veith et al. 1983 Konemann 1981). In exploring this relationship with recently published data on the LC50 of aliphatic alcohols, ketones, esters and nitriles, the relationship was found to hold generally. There were some visual outliers (not necessarily statistically significant). The structure of most of these outliers is similar in that they are potentially anionic in contrast with the electrophilic outliers seen by Lipnick et al. (1985). 

For the nonpolar side chains of amino adds, Ala Val, Leu, and Phe, there is a linear relationship between hydrophobicity and accessible surface area. The slope is equivalent to 22 cal A For the side chain residues with hydroxylic groups, the slope is 26calA (Chothia, 1974). This linear dependency is shown in Fig. 3.12. Chothia (1974, 1975, 1976) and Janin (1976) determined that the loss of accessible surface area in monomeric proteins after folding is proportional to the hydrophobic energy and is a simple function of their molecular weight it is proportional to the two-thirds power of their molecular weight (Fig. 3.13) (Janin, 1976). 

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