Behdad Delavari - Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran- Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran, Iran
Ali Akbar Saboury - Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
Atieh Ghasemi - Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
Fatemeh Mamashli - Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran

Doxorubicin, a powerful chemotherapeutic agent, is a conventional drug used in treatment of breast cancer. However, hydrophobic nature of doxorubicin makes its medical application difficult. Therefore, introducing a way to facilitate its employment in medicine is desirable. Alpha lactalbumin, the second most abundant milk whey protein, can be a potential carrier for doxorubicin. In the current study, the authors aimed at evaluating the interaction of doxorubicin and alpha lactalbumin to determine alpha lactabumin‟s potential to be used as a carrier for doxorubicin. Isothermal titration calorimetry revealed presence of one binding site for doxorubicin on alpha lactalbumin. Besides, K, ΔH, ΔS, and ΔG values were obtained as 6.7×103 M-1, -6.8 kcal/mol, -5.37 cal/mol K, and -5.22 kcal/mol, respectively, for alpha lactalbumin upon interaction with doxorubicin. Furthermore, no significant change in the fluorescence lifetime values of alpha lactalbumin alone and after interaction with doxorubicin indicated that the interaction between them is static. Moreover, measurement of anisotropy values of alpha lactalbumin before and after interaction with doxorubicin presented decreased values of anisotropy upon interaction with doxorubicin which can be due to formation of protein assemblies after doxorubicin binding. In conclusion, the authors suggest that alpha lactalbumin can serve as a suitable carrier for doxorubicin.

Alpha Lactalbumin, Doxorubicin, Isothermal Titration Calorimetry, Fluorescence lifetime, Anisotropy