Effect of pH on β-Lactoglobulins

Association behavior of native ?-lactoglobulin

“…24,25 A pH rise above 8.0 induces time-dependent, irreversible aggregation of ␤-lg, which is stronger at 4°C than at 20°C and is caused by the formation of intermolecular disulfide bonds. 7,26,27 The tertiary structure of ␤-lg has been characterized by x-ray crystallography. 4,28 -30 The structure mainly consists of antiparallel ␤-sheets.…”

“…These observations are consistent with the literature (see Introduction). From the literature values of ␤-lg monomer-dimer 7,10,[12][13][14]18,19,22 association constants below pH 4 and above pH 5.2 and dimer-octamer 6,11,20 association constants between pH 4 and 5.2, we calculated the weight-averaged molecular mass of the protein in a 9 mg mL values from our SANS experiments (9 mg mL Ϫ1 ␤-lg, 0.1M NaCl). The M av values obtained in the present study agree well with the literature values and apart from the statistical and systematic errors, differences may be due to differences in properties between H 2 O and D 2 O.…”

On the Dissociation of Bovine ,b-Lactoglobulins A, B, and C Near Ph 7

“…When measurements were carried out following standing of the solutions it was found that there were slow increases with time in 8, the increase being greater at pH 8·8 than 8 ·2. Similar time-dependent effects were observed in electrophoresis (McKenzie and Sawyer 1966). ----________ :::- • Experimental points for the A variant at pH 6· 0, 7· 5, 8· 2, and 8· 8.…”

Facile synthesis of β-lactoglobulin capped Ag2S quantum dots for in vivo imaging in the second near-infrared biological window

“…fraction of dissociated protein increases with increasing temperature from -15 to 85 o C 55 . One of the most important consequences of these conformational changes is the exposure of the free thiol C LG formation of intermolecular disulfide bonds 56,57 .…”