Fig 4. Effect of riboflavin on cell proliferation and viability, and on expression and enzymatic activity of hPPO.

A; Dependence of cell proliferation on riboflavin media supplementation. Cells were grown in media with or without riboflavin supplementation. B; Cell viability in medium with or without riboflavin was determined by Trypan blue assay. C; The expression yield of HALO-hPPO in the presence/absence of riboflavin in cultivation media. Fractions eluted from Streptactin affinity column were visualized by Coomassie-stained SDS-PAGE. D; The influence of media supplementation with riboflavin on enzymatic activity of hPPO constructs expressed by HEK293T17 cells.