Figure 4. Rates of phosphorylation and dephosphorylation of Cdc25.

Simulations (lines) are compared to experimental data (circles) estimated from Kumagai et al. 1992, Figure 10. The phosphorylation of Cdc25 during M phase was monitored by gel-shift of endogenous Cdc25, and the dephosphorylation of Cdc25 during interphase was monitored by loss of ³²P from radioactively phosphorylated, exogenous Cdc25 added to an extract. The theoretical curves were computed from the full model (Table 2) and the final parameter set (Table 3). Assumptions: [MPF] = 100 nM in M phase; = 0 in interphase.