Figure 2.

TiO₂ beads purify nucleotides and inositol phosphates from mammalian cells. (a) PA extracts from vegetative D. discoideum (4 × 10⁶ cells) and the human HCT116 cell line (80 × 10⁶ cells) were subjected to TiO₂ enrichment. After resolving the extract with PAGE, phosphate-rich molecules were visualized by toluidine blue staining for comparison with InsP₆, ATP and GTP nucleotide standards. (b) TiO₂-purified HCT116 extract and nucleotide standards were subjected to apyrase treatment, before resolution by PAGE and staining with toluidine blue. (c) Two 14 cm dishes of 80% confluent HeLa, HCT116 and MCF7 cells were treated with 10 mM sodium fluoride (NaF) for 1 h, before purification of inositol phosphates with TiO₂ beads and resolution by PAGE with toluidine blue staining. The gels presented are representative of experiments performed at least three times.