Hexagonal aggregation

Figure 12.6 Liquid-crystalline phases and catalytic activity of peroxidase in ternary water/surfactant/organic solvent phases (Martinek, 1986). Phases a = normal micelles b = reversed micelles c = lamellar aggregates d = hexagonal aggregates.

Lipoamino acids are also particularly attractive as antiviral agents. Certain acylamino acid derivatives have been found to produce inhibition on influenza neuraminidase [30]. A number of V -palmitoylated amino acids/peptides have been incorporated into model membranes affecting the transition temperature between the bilayer to hexagonal aggregation, a property associated with antiviral activity. Epand et al. [31] demonstrated the inhibition action of A -palmitoyltryptophan against the Cantell strain of Sendai virus (parainfluenza type 1). 

The structure established by Bradley [1940] is rather unusual. It is, in fact, constituted by layers of tetrahedrons forming an hexagonal aggregate and, contrarily to other clays, the tetrahedral groups are directed sometimes upward, sometimes downward, in relation to a plane ( trans position). 

Cry staUization at temperatures of about 40°C results in heavy nucleation and a fine product. At temperatures above 75°C, only cry stal growth occurs, giving rise to large, weU-cry staUized aggregates composed of hexagonal rods and prisms (Fig. 2a). 

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