Fig. 4.

Biotin alters the intracellular levels of certain amino acids. Reverse-phase HPLC was carried out determine the intracellular levels of amino acids. The cells were lysed on the sixth day of differentiation, and the lysate volumes across samples were adjusted to a uniform DNA concentration using cell lysis buffer containing norleucine as internal standard. Equal volumes of lysate were delipidated, deproteinized, and PITC-derivatized for amino acid analysis using HPLC. The AUC value of each analyte was normalized against norleucine and subjected to relative quantification. Symbols * and # indicate a p value < 0.05 significance compared with control and biotin-treated group (n = 4), respectively