Volume interactions with proteins

The ability of an amphiphilic molecule to interact with protein is an important characteristic of a food emulsifier because it contributes to the volume of any baked product. The mechanism of such an interaction is not yet clear. Some investigators claim that the hydrophilic head, via its carboxylic groups, interacts with the free amino groups of the protein and serves as a cross-linker to another protein. Other investigators think that the emulsifier interacts with the hydrophobic sites of the protein via hydrophobic interaction. In any event, the emulsifier forms additional compartments in which the gas released from the yeast will be entrapped. 

Uses of 1. are numerous. The most important outlet is ->food additives. Due to its interaction with proteins, it is used in baked goods to improve volume, disperse fat easier and to act as an antioxidant. It... 

The inhibition of amino-acid transport has been regarded as the main toxic effect of mercury compounds [82], The biochemical mechanism underlying the inhibition is unclear. In unfertilized sea-urchin eggs an interaction with the amino-acid carrier was found, whereas in fertilized eggs inhibition of amino-acid transport was indirect and might result from an elevation of the Na + content of the egg caused by the inhibition of the Na+ pump [83]. The action on the diffusional process could be mediated by an effect on membrane phospholipids or on membrane proteins, or by interaction with Ca2+ which stabilizes membrane structure. Mercuric chloride in skate liver cells inhibited amino acid transport, decreased Na + /K + -ATPase (adenosinetriphosphatase) activity, impaired volume regulatory mechanisms and increased the permeability of the plasma membrane to potassium [84]. It has been suggested that... 

Results from thermal denaturation and heat capacity studies have shown that the proteins are not necessarily completely unfolded in this process. The volume observations also suggest that the denatured state is not one in which all hydrophobic groups are exposed to water. But the results can also be understood from the effect of close polar and electrostatic groups interacting with the water structure surrounding the hydrophobic groups. The volume change is heavily... 

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