Fig. 3. Effect of synthetic PG on the release of ATP from the ORC-ATP complex. ORC (0.15 pmol) was pre-incubated with 0.2 mM [a-³²P]ATP at 4°C for 10 min, and further incubated with or without 10 mg of CL, PG (egg yolk), PG (18:0), or PG (18:2) for the indicated periods at 30°C. The amount of bound ATP was determined by a filter-binding assay. Values are mean ± SD, n = 3.