Effect of Beta-lactoglobulin in oxidatively stressed yeast Saccharomyces cerevisiae cells

Abstract

Beta-lactoglobulin (β-Lg) is the most abundant protein in the serum of bovine milk. However, it should be mentioned that this protein is absent in human milk. According to previous studies, the peptides contained in β-Lg are precursors of glutathione.

Glutathione is a powerful antioxidant produced by human cells to maintain oxidation- reduction balance. Therefore, we theorize that β-Lg may have antioxidant effects. There

are no studies in the literature that test this idea. The objectives of this study are to establish a method to induce oxidative stress in yeast Saccharomyces cerevisiae and to evaluate if β-Lg exerts a protective effect on these oxidatively challenged cells. First, we needed to determine if β-Lg had an effect on cellular viability. None of the concentrations tested had an effect on the viability of cells (P=0.1674). Different ways of inducing oxidative stress in yeast were analyzed, among them: exposure to C-type ultraviolet radiation, dihydrogen peroxide, menadione and menadione sodium bisulfite (MSB). The compound that produced the most reliable results was MSB. 40% of cell death was achieved using 0.5 mM MSB. MSB-treated cells were co-incubated with 6.25 mg / mL of β-Lg. The results show that the yeast treated with β-Lg had a 10.94% higher surviving rate than the cells with no β-Lg (P <0.0001). These results suggest that the β-Lg protein exerts a protective effect on oxidatively stressed cells.