Figure 2. Purity of PP-InsP preparations.

HPLC (see the Materials and methods section) of 5-[³H]InsP₇ (A), 1-[³H]InsP₇ (B) and [³H]InsP₈ (C). The purities of 5-[³H]InsP₇, 1-[³H]InsP₇ and [³H]InsP₈ were 91, 98 and 92%, respectively. (D) Toluidine Blue-stained PAGE analysis (16 cm gel) of purity of non-radiolabelled PP-InsP preparations (20 nmol/lane). The image was enhanced in ImageJ [54] by increasing contrast and smoothing. Purity was quantified by densitometric analysis (right-hand panels) of the central portion of each lane as indicated by the rectangles in each of the left-hand panels using ImageJ [54]. Commercial InsP₆ (not further purified) served as a control. Purity was as follows: 5-InsP₇, 96%; 1-InsP₇, 98%; and InsP₈, 97%.