Changes in the Secondary Structure of Bovine Casein by Fourier Transform Infrared Spectroscopy: Effects of Calcium and Temperature

121Citations
Citations of this article
77Readers
Mendeley users who have this article in their library.
Get full text

Abstract

Bovine casein submicelles and reformed micelles, produced by addition of Ca2+, were examined by Fourier transform infrared spectroscopy at 15 and 37°C in aqueous salt solutions of K+ and Na+. Previous measurements of caseins, made in D2O and in the solid form, can now be made in a more realistic environment of H2O. When analyzed in detail, data obtained by Fourier transform infrared spectroscopy have the potential to show subtle changes in secondary structural elements that are associated with changes in protein environment. Electrostatic binding of Ca2+ to casein resulted in a redistribution of the components of the infrared spectra. Addition of Ca2+ in salt solutions of K+ and Na+ led to apparent decreases in large loop or helical structures at 37°C with concomitant increases in the percentage of structures having greater bond energy, such as turns and extended helical structures. At 15°C, Na+ and K+ have differential effects on the Ca2+-casein complexes. All of these observations are in accordance with the important role of serine phosphate side chains as sites for Ca2+ binding in caseins and the swelling of the casein structure upon incorporation into reformed micelles at 37°C. This new open, hydrated structure is buttressed by a change in backbone as evidenced by a shift in absorbance to higher wave numbers (greater bond energies) as colloidal micelles are reformed.

Cite

CITATION STYLE

APA

Curley, D. M., Kumosinski, T. F., Unruh, J. J., & Farrell, H. M. (1998). Changes in the Secondary Structure of Bovine Casein by Fourier Transform Infrared Spectroscopy: Effects of Calcium and Temperature. Journal of Dairy Science, 81(12), 3154–3162. https://doi.org/10.3168/jds.S0022-0302(98)75881-3

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free