Calcium binding and salt-induced structural changes of native and preheated .beta.-lactoglobulin

Calcium binding to β-lactoglobulin in the native and preheated forms was studied using an ion-selective electrode, and the structural changes induced were studied by fluorescence spectroscopy. Ca binding to β-lactoglobulin showed a small increase with heat treatment and a larger increase with pH. The intrinsic fluorescence of β-lactoglobulin and aniline naphthalenesulfonate fluorescence showed significant increases with heat treatment and with the addition of CaCl 2 (1-15 mM). The reactive sulfhydryl group content also increased with the addition of CaCl 2 to native and preheated β-lactoglobulin