Hydrophobic interaction of lysozyme and alpha-lactalbumin from equine milk whey.
From fluorescence measurements on mixtures of bis-ANS and equine lysozyme and from Ca(2+)-dependent hydrophobic interaction chromatography of equine lysozyme, it is demonstrated that Ca2+ binding induces a conformational change upon which hydrophobic regions in the protein become less accessible. Bis-ANS fluorescence titrations in the absence of Ca2+ and in 2 mM Ca2+ are also performed with equine alpha-lactalbumin variants B and C. These variants differ by an amino-acid exchange Asp----Ile at residue 95. The fluorescence titration curves indicate that the accessibility of the probe to the Ca2+ conformers is clearly influenced by the mutation. The Ca(2+)-dependent exclusion of a hydrophobic domain is used in a new and simplified method for preparing lysozyme and alpha-lactalbumins simultaneously from equine milk whey.
Haezebrouck
P
P
Interdisciplinary Research Center, K.U.L. Campus Kortrijk, Belgium.
Noppe
W
W
Van Dael
H
H
Hanssens
I
I
D000817:Anilino Naphthalenesulfonates; D000818:Animals; D002118:Calcium; D002845:Chromatography / Q000379:methods; D005456:Fluorescent Dyes; D006736:Horses; D007768:Lactalbumin / Q000737:chemistry* / Q000302:isolation & purification; D008892:Milk / Q000032:analysis*; D008894:Milk Proteins / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry* / Q000302:isolation & purification; D000067816:Whey Proteins
D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D008894:Milk Proteins; D000067816:Whey Proteins; C035763:5,5'-bis(8-(phenylamino)-1-naphthalenesulfonate); D007768:Lactalbumin; D009113:Muramidase; D002118:Calcium