{ diff(x11, t) = 0/k70,
  diff(x1, t) = k12*k8 - k10*x1,
  diff(x2, t) = k14*k9*1/(1 + (x12/k50)^k67) - k11*x2,
  diff(x3, t) = k16*(k61 + (x1/k45)^k64)/(1 + (x1/k45)^k64 + (x10/k49)^k69) - k23*x3,
  diff(x4, t) = k30*x3 - k38*x4,
  diff(x5, t) = k17*(k63 + (x1/k45)^k64)/(1 + (x1/k45)^k64) - k24*x5,
  diff(x6, t) = k31*x5 - k39*x6,
  diff(x7, t) = k18*(k62 + (x2/k46)^k65)/(1 + (x2/k46)^k65 + (x4/k47)^k68) - k25*x7,
  diff(x8, t) = k32*x7 - k40*x8,
  diff(x9, t) = k51 - k52*x9 - k55*x9*x16,
  diff(x10, t) = k29*x9 - k37*x10,
  diff(x12, t) = k36*x11 - k44*x12,
  diff(x13, t) = k20*k58 - k27*x13,
  diff(x14, t) = k19*(k59 + (x8/k48)^k66)/(1 + (x8/k48)^k66) - k26*x14,
  diff(x15, t) = k21*(k60 + (x8/k48)^k66)/(1 + (x8/k48)^k66) - k28*x15,
  diff(x16, t) = 0 }