Abstract

Background: Various animal milks and their dairy products are very popular among Mongolian people. In case of Bovine milk, α-lactalbumin (αLA) and β-lactoglobulin (βLG) are involved in whey fraction, which have function to bind lipid, fatty acid, and hydrophobic molecules as lipocalin. On the other hand, the function of whey proteins corresponding to these proteins in Mongolian animal milks, such as Goat, Horse, and Camel, might be poorly understood. On the other hand, the function of whey proteins corresponding to these proteins in Mongolian animal milks, such as Goat, Horse, and Camel, might be poorly understood.
Aim: The main aim to prepare why proteins in Mongolian Goat, Horse, and Camel milks and explore the binding properties to fatty acids, lipids, and hydrophobic molecules by fluorescence spectrometry.
Method: Firstly, we prepared each αLA and βLG from each whey fraction of Goat, Horse, and Camel milks, which were collected at Mongolia. Then, we obtained about 1-4mg of five whey proteins (namely gLA, gLG, hLA, hLG, and cLA). Protein concentration was adjusted to 0.05mg/ml, followed by measured their fluorescence spectra with or without six fatty acids and seven hydrophobic molecules, by using internal Tyr residues as probe.
Result: We found that each Tyr-excited fluorescence spectra was significantly quenched by adding 1-Naphthol, Vitamin B1, AMA, Quercetin, Retinol, and 8-ANS (final concentration 100μM), whereas slight decrease (74-93% remaining) of fluorescence intensity was observed in each whey proteins, when fatty acids were added. Accordingly, it was suggested that these whey proteins have ability to bind to hydrophobic and aromatic molecules with polar group(s) partially.
Conclusion: It was observed that their fluorescence spectra were quenched (less than 20% remaining) and maximum wavelength shifted remarkably when Quercetin, Retinol, and 8-ANS added. Furthermore, we evaluated Kd values of five whey proteins for Vitamin B1, AMA, Quercetin, Retinol, and 8-ANS, and it was revealed that these whey proteins have specific binding to hydrophobic and aromatic molecules with polar group(s) partially.