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Updated: Jun 15, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Fourier transform infrared spectroscopic study of molecular interactions in hemoglobin
Abstract:
Infrared absorption spectra of the alpha-104 (G11) cysteine SH group have been observed for aqueous solutions of hemoglobin derivatives from humans, pigs, and horses. The center frequencies ((nu)SH) show ligand sensitive patterns that are similar for the three species, with (nu)SH (HbCO) <(nu)SH (HbO(2) ~ HbCN) < (nu)SH (Hb(+)) <<(nu)SH (deoxyHb) for human and pig hemoglobins. The alpha-104 SH group is most strongly H-bonded (smallest (nu)SH), has the greatest range of (nu)SH (Hb ? HbCO) in human hemoglobin, and is least strongly H-bonded and has the smallest range of (nu)SH (Hb ? HbCO) in horse hemoglobin. The beta-112 cysteine SH in human hemoglobin is more weakly H-bonded than is the alpha-104 SH. These studies illustrate how FTIR can be used to measure differences in protein structure that are related to biological control mechanisms.
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