Rigidifying effect

Tsuchiya H, Nagayama M, Tanaka T et al. Membrane-rigidifying effects of anti-cancer dietary factors. Biofactors 16 (3-4), 45-56, 2002. 

In a more detailed study Caturla et al. [112] investigated the interaction of four catechins with PC and PE model membranes by fluorescence spectroscopy, microcalorimetry, and infrared spectroscopy. DPH fluorescence anisotropy was monitored as a function of temperature and it was observed that catechins either did not change or increased DPH anisotropy. The membrane rigidifying effect of (-)-epicatechin (EC) (37b) was the most... 

In this trail the experimental premise was that if taking a common membrane PL such as phosphatidylcholine (PC) and comparing one species with an oleoyl (18 1) sn-2 acyl tail to another, with a linoleoyl (18 2) one, the latter would possess a greater area. Contrariwise, within a given field, more molecules of an oleoyl PC species would be able to be packed and thus in keeping with the experimental surmise detailed in a above, should have a rigidifying effect on the membrane. 

FIGURE 4.3 Transbilayer variations of cholesterol content in brain membranes. (A) In young individuals, cholesterol is enriched in the cytoplasmic leaflet of the plasma membrane, both in Upid rafts (Lo phase) and in the bulk membrane (Ld phase). (B) In older subjects, cholesterol is less abundant in the cytosolic leaflet and occurs in higher amounts in the exofacial leaflet, espedaUy in the Ld phase where it may exert a rigidifying effect. 

Polylysine had the most pronounced rigidifying effect (AP 0.05) (Fig.7b). Polycationic branched polypeptides (AK, SAK, OAK) had moderate (AP=0.01-0.04), while amphoteric (EAK) and polyanionic (Ac-EAK) derivatives had no influence on polarisation. Presence of polycationic polypeptides increased the transition temperature (ATc +0.5-1.3 C) and widened the temperature range of the phase transition, indicating that penetration of polymeric polypeptides into phospholipid bilayers resulted in increased distance of phospholipid molecules. 

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