Binding of calcium ions to bovine β-casein

Abstract

SummaryThe isotherms for Ca2+ binding to bovine β-casein have been measured at 5 temperatures in the range 4–40 °C and at 4 different ionic strengths. The results are interpreted by an interactive-site binding model, and are compared with results previously obtained on αs1-casein. The affinity of β-cesein for the first Ca2+ to bind is similar to the affinity of αsl-casein for the same binding event: however, binding of subsequent Ca2+ to β-casein is weaker than the binding to αs1-casein. The results are discussed in terms of precipitability of the 2 caseins caused by the binding of Ca2+.