{ diff(x1, t) = k1*k4^k39/(k4^k39 + x2^k39) - (k2*x1/(k3 + x1) + k22*x1),
  diff(x2, t) = k18*x3 - (k19*x2 + k17*x2),
  diff(x3, t) = k20*x10*x4 + k19*x2 - (k21*x3 + k18*x3 + k16*x3),
  diff(x4, t) = k28*x5/(k36 + x5) + k21*x3 - (k30*x4/(k38 + x4) + k20*x10*x4 + k14*x4/(k15 + x4) + k22*x4),
  diff(x5, t) = k24*x6/(k32 + x6) + k30*x4/(k38 + x4) - (k26*x5/(k34 + x5) + k28*x5/(k36 + x5) + k22*x5),
  diff(x6, t) = k13*x7 + k26*x5/(k34 + x5) - (k24*x6/(k32 + x6) + k22*x6),
  diff(x7, t) = k9*k12^k39/(k12^k39 + x2^k39) - (k10*x7/(k11 + x7) + k22*x7),
  diff(x8, t) = k6*x1 + k25*x9/(k33 + x9) - (k23*x8/(k31 + x8) + k22*x8),
  diff(x9, t) = k23*x8/(k31 + x8) + k29*x10/(k37 + x10) - (k25*x9/(k33 + x9) + k27*x9/(k35 + x9) + k22*x9),
  diff(x10, t) = k27*x9/(k35 + x9) + k21*x3 - (k29*x10/(k37 + x10) + k20*x10*x4 + k7*x10/(k8 + x10) + k22*x10) }