The following is an abstract for the selected article. A PDF download of the full text of this article is available here. Members may download full texts at no charge. Non-members may be charged a small fee for certain articles.

Fourier Transform Infrared Study of Lipoxygenase Conformation in Organic Solvent Media

Volume 60, Number 2 (Feb. 2006) Page 168-173

Vega, Mireille; Ismail, Ashraf; Sedman, Jacqueline; Kermasha, Selim

The secondary structure of commercially purified soybean lipoxygenase (EC was investigated in selected monophasic organic solvents, including chloroform, methanol, acetonitrile, hexane, and octane. The Fourier transform infrared (FT-IR) spectra of the enzyme obtained in chloroform, methanol, and acetonitrile showed an absorption band at 1617 cm−1 indicative of significant protein aggregation, whereas spectra of lipoxygenase in hexane and octane exhibited substantially less aggregate formation. Variable-temperature infrared studies of lipoxygenase in D2O show that the predominately α-helical structure of the protein undergoes an irreversible transition to intermolecular β-sheet at and above 65 °C. Chemical imaging technology employing an FT-IR spectrometer equipped with an infrared microscope and a focal-plane array detector was used to examine the changes in the secondary structure of lipoxygenase at the water-hexane interface in the presence and absence of substrate. The secondary structure of lipoxygenase at the hexane-water interface was comparable to that of the structure of lipoxygenase in D2O after exposure of lipoxygenase solution to hexane.