Second derivative FTIR spectra in the amide I region of CK in D2O (pD 8.45, uncorrected value) incubated at 50°C (A) and kinetic course of the aggregation of CK in Tris-HCl buffer (pH 8.0) incubated at 50°C in various concentrations of glycerol monitored by turbidity at 400 nm (B). The arrows in A indicate the direction of the intensity changes along with incubation time, and the wavenumbers indicated are 1682, 1666, 1660, 1651, 1639, 1629, and 1614 cm−1, respectively.