Related Experiment Video
Updated: Aug 11, 2026

Mass Spectrometric Approaches to Study Protein Structure and Interactions in Lyophilized Powders
Published on: April 14, 2015
Secondary structures of proteins adsorbed onto aluminum hydroxide: infrared spectroscopic analysis of proteins from
Aichun Dong1, LaToya S Jones, Bruce A Kerwin
1Department of Chemistry and Biochemistry, University of Northern Colorado, Greeley, CO 80639, USA. aichun.dong@unco.edu
Abstract:
Comparative studies of the secondary structures of six model proteins, adsorbed onto aluminum hydroxide gel (Alhydrogel) or in aqueous solution, were carried out by Fourier transform infrared (FTIR) spectroscopy. The analysis of high-quality spectra of all six model proteins, with a broad range of secondary structure compositions, obtained at 15 mg/ml by the conventional method and at 0.5 and 1.0 mg/ml adsorbed to Alhydrogel revealed that adsorption onto hydrophilic surfaces of aluminum hydroxide particles did not alter the secondary structures of the proteins. The results of this study suggest that adsorbing proteins to Alhydrogel provides a means of obtaining FTIR spectra to study secondary structure and conformational changes of proteins in aqueous solution at very low concentrations. The new procedure effectively lowers the concentration requirement for FTIR studies of proteins in aqueous solutions by at least 40-fold, as compared with the conventional FTIR method. It permits FTIR study of proteins to be carried out in the same concentration range as is used for circular dichroism and fluorescence, thereby making it possible to compare structural information obtained by three commonly used techniques in protein biophysical characterization.
Related Concept Videos
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
NMR Spectroscopy and Mass Spectrometry of Aldehydes and Ketones
IR Spectrum Peak Broadening: Hydrogen Bonding
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular hydrogen bonding...
IR Frequency Region: X–H Stretching
Atomic Absorption Spectroscopy: Lab
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
Protein Organization
The primary structure of a protein is its amino acid sequence.

