B. Lieske et G. Konrad, DETERMINATION OF SURFACE HYDROPHOBICITY OF MILK-PROTEINS - COMPARISONBETWEEN A NEW DETERGENT BINDING METHOD AND HYDROPHOBIC INTERACTION FPLC, Milchwissenschaft, 50(1), 1995, pp. 10-13
A previously published method for the determination of the surface hyd
rophobicity of proteins using BIO-RAD protein assay combined with Twee
n 80 was adopted to various milk proteins. The relative retention time
s obtained by HI-FPLC at Phenyl-Superose for casein and whey protein w
ere compared with results of the proposed method and expanded by the a
verage hydrophobicity calculated according to BIGELOW. Detergent bindi
ng showed good correlation with calculated average hydrophobicities fo
r all milk proteins, whereas HI-FPLC results were found to be accurate
only for caseins. The relative order of hydrophobicity for single cas
eins was pH dependent. In contrast, HI-FPLC was found to be not select
ive for separation of whey proteins according to their hydrophobicity,
but selective for the solubility characteristics related from the use
d buffer system. Evidence is given that this proposed method can be ea
sily performed, is highly reliable and adaptable to a rapid quantitati
ve differentiation between hydrophobic and hydrophilic areas on protei
n surfaces.