Figure 1.

Standard normal variate-normalized absorbance spectra of amyloidosis-affected cardiac tissue (blue line) and post-transplant control cardiac tissue (green line) in the spectral region of 1750–1000 cm⁻¹, illustrating the associated biomolecules represented by the wavenumbers in the mid-infrared region. The amide I band (1700–1600 cm⁻¹) arises by C=O stretching vibrations, indicative of protein secondary structure. The amide II band (1700–1600 cm⁻¹) represents N-H bending coupled with C-N stretching and the amide III band (1300–1200 cm⁻¹) contains a mixture of C-N stretching and N-H bending, which are also related to protein structure.