STIL is labile to microwave-assisted acid hydrolysis. A, Dilution series of the LePRK2 dephosphorylating activity of pure STIL. Lane 1, untreated pollen microsomal fraction. Lane 2 was treated with 4.8 × 10-2 Abs280 units of tobacco style extract. Serial dilutions of purified STIL (lanes 3 through 14, from Fig. 2C) were used in the dephosphorylation assay; B, Pollen microsomal fractions were untreated (lane 1) or treated with tobacco style extract (lane 2), or with 1.44 Abs280 units (lanes 3, 6, 9 and 12), 0.72 Abs280 units (lanes 4, 7, 10 and 13) or 0.36 Abs280 units (lanes 5, 8, 11 and 14) of partially purified STIL (C18 percolate). Before the dephosphorylation assay was carried out, partially purified STIL (C18 percolate) was pre-treated by microwave-assisted acid hydrolysis (lanes 3-5). Lanes 6-8, salt concentration control. Lanes, 7-10, high temperature control. Lanes, 11-14, sample dilution control. The position of LePRK2 is indicated by an arrow.