FT‐IR study of the Ca²⁺‐binding to bovine α‐lactalbumin

Abstract

Fourier-transform infrared spectroscopy (FT-IR) was applied to examine relationships between the type of coordination and the COO- antisymmetric and symmetric stretches of the COO- groups in the Ca2+-binding site of bovine alpha-lactalbumin. The peaks at 1593, 1578, 1425, and 1403 cm(-1) were assigned to the COO- groups of Asp-82, 87, and 88 coordinating to Ca2+ in the pseudo bridging mode, according to the results of X-ray crystallography. The bands due to the COO- groups were quite similar to each other between alpha-lactalbumin and EDTA which is the model compound for the pseudo bridging state.