Fl-Lactoglobulin

Figure 4.21 Monitoring of an enzyme reaction using size-exclusion liquid chromatography. Column, TSK GEL G3000SW, 60 cm x 7.5 mm i.d. eluent, 0.07 M potassium phosphate buffer containing 0.1 M potassium chloride flow rate, 1 ml min-1 detection, UV 280 nm. Peaks 1, fl-lactoglobulin 2, a-chymotrypsin, and 3, decomposed products.

Figure 4. Denaturation of M-fi-L added to skim milk compared with that of endogenous fi-lactoglobulin in milk following 30 min heating at various temperatures O, denaturation of endogenous fl-lactoglobulin (12) , denaturation of M-/3-L added to skim milk. A range for triplicates of more than 2% is indicated by a bar (10).

Self-assembly of Acacia Gum and fl-Lactoglobulin in Aqueous Dispersion... 

The /1-casein (jS-CS) and /J-lactoglobulin (jS-LG) from bovine milk were obtained from SIGMA. Molecular weights of 24000 for fi-CS and 18 400 for fl-LG were used. The protein samples were used without further purification. The solutions were prepared with phosphate buffer made by mixing appropriate stock solutions of Na2HP04 and NaH2P04. The surface tension of a 10 mM buffer at pH = 7 was 72.7 mN/m. All measurements were performed at room temperature of 22 °C. 

A much more complex behaviour is observed for the process of penetration of various proteins into phospholipid monolayers. This behaviour depends strongly on the protein and the solution properties although some common features are observed. Fainerman et al. [116] studied the P-lactoglobulin penetration dynamics into DPPC monolayers. For a (i-lactoglobulin bulk concentration of 510 mol/l and molar areas of the lipid larger than the critical value, A > A, first order phase transitions are observed. Thus, two-dimensional condensed phase are formed although at these molar area values the pure DPPC monolayer exists only in the fluid-like state and does not form any domains. The first-order phase transition in the DPPC monolayer becomes visible by the characteristic break point in the dynamic surface pressure curve Fl(t) (see Fig. 4.50). 

Fig. 3. Aqueous solution spectra in a 6 nm thick Cap2 liquid cell (A) absorbance spectrum of pure H2O (B) absorbance spectrum of 10% solution of 8-lactoglobulin (C) the resulting spectrum after subtraction fl-A...

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