Proteins P-lactoglobulin

We turn now to the other major whey protein, p-lactoglobulin. This is an acidic globular protein (p/= 5.1) with a molar mass of 18.4 kDa and a radius of about 2 nm (Aymard et al., 1999). The protein can form long semi-flexible fibrils when heated in solution at around or above its dena-turation temperature (60-80 °C) at pH = 2 and low ionic strength (Durand et al., 2002 Veerman et al., 2002, 2003a,b). (An example of the... 

Cell surfaces of body tissues appear to contain receptors for the retinol-binding protein. Many cells also contain cytoplasmic retinolbinding proteins " as well as proteins that bind retinoic acid. 5 These proteins are members of the large superfamily of hydro-phobic transporter molecules described in Box 21-A. This includes the milk protein P-lactoglobulin, which also forms a complex with retinol. ... 

The lactoglobulin fraction consists mainly of immunoglobulins (Ig), especially IgGj, with lesser amounts of IgGj, IgA and IgM (section 4.10). The lactalbumin fraction of bovine milk contains three main proteins, p-lactoglobulin (jS-lg), a-lactalbumin (a-la) and blood serum albumin (BSA), which represent approximately 50, 20 and 10% of total whey protein, respectively, and trace amounts of several other proteins, notably lactotrans-ferrin, serotransferrin and several enzymes. The whey proteins of sheep, goat... 

Recently, the competitive adsorption dynamics of phospholipid/protein mixed system at the chloroform/water interface was investigated by using the drop volume technique. The three proteins P-Lactoglobulin, P-Casein, and Human Serum Albumin were used in this study. To investigate the influence of the phospholipid structure at concentrations close to the CAC (critic aggregation concentration) the four lipids dipalmitoyl phosphatidyl choline (DPPC), dimyristoyl phosphatidyl choline (DMPC), dimyristoyl phosphatidyl ethanolamine (DMPE)... 

Gosal WS, Clark AH, Pudney (2002) Novel amyloid fibrillar networks derived from a globular protein p-lactoglobulin. Langmuir 18 7174-7181... 

Baussay K, Le Bon C, Nicolai T et al (2004) Influence of ionic strength on the heat-induced aggregation of the globular protein p-lactoglobulin at pH 7.0. Int J Biol Macromol 34 21-28... 

Fig. 1.31. Arrhenius diagram for the denaturation of the whey proteins p-lactoglobulin A, p-lactoglobulin B and a-lactalbumin B (according to Kessler, 1988)...

It is beyond the scope of this chapter to analyze in detail the various surface interactions and forces that proteins can provide. The number of amphiphilic proteins in the world of proteins is limited, which means that the proteins in use are mainly caseins, whey proteins, P-lactoglobulins (BLGs), egg albumin, bovine semm albumin (BSA), lysozyme, and soy proteins. All other plant proteins have very limited ability to strongly adsorb onto interfaces and reduce interfacial tension to only a minor extent. However, chemical and enzymatic modifications will improve the performance of these proteins (pea, cotton, and cereal proteins), and as a result a few modified proteins can be found in the marketplace that have relatively improved performance. 

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