Thermodynamic analysis of albumin interaction with monosodium glutamate food additive: Insights from multi-spectroscopic and molecular docking approaches

Monosodium glutamate (MSG) is an example of food additive, which is used as a flavor enhancer in various foodstuffs. Because of its extensive use in food production, the toxicology and possible negative effects of MSG additive on albumin must be well investigated. Therefore, for the first time, the binding of BSA and MSG have been studied using multispectroscopic and molecular modeling approaches under physiological conditions. BSA fluorescence intensity has been diminished upon the addition of increased MSG concentrations. The Stern-Volmer quenching constant (K-sv) value increase with rising temperature and bimolecular quenching rate constant of protein (k(q) ) value was larger than 2.0 x 10(10) L mol(-1) s(-1), which shows that the fluorescence quenching was both dynamic and static due to the BSA-MSG complex formation. The positive values for both Delta S-0 (888.291 J mol(-1) K-1) and Delta H-0 (243.903 kJ mol(-1)) proposed that the hydrophobic forces played predominant roles in the binding of MSG to BSA. Also, the negative value of Delta G(0) indicated that the interaction between two compounds is spontaneous and enthalpy driven. The UV-VIS spectra results confirmed the binding of MSG to BSA. The circular dichroism analysis exhibited that BSA conformation change occur upon interaction with MSG. Moreover, molecular modeling analysis indicated that glutamate remarkably tends to bind into a cavity above Sudlow II with lowest calculated binding energy of - 8.24 kcal/mol. (C) 2020 Elsevier B.V. All rights reserved.