x1 = Cdc25_active
x2 = Cdc25Ps216_active
x3 = Cdc25_inactive
x4 = Cdc25Ps216_inactive
x5 = Chk1P
x6 = protein_14_3_3
x7 = Cdc25Ps216_14_3_3_inactive
x8 = p53
x9 = p21
x10 = MPF
x11 = p21_MPF
x12 = preMPF
x13 = Wee1
x14 = Chk1
x15 = Rad3_ATM
x16 = Wee1_phosphorylated
x17 = Cdc25_active_total