[ Eq(Derivative(x1, t), (1*k2*(k27 + k28*x18**k29/(k30**k29 + x18**k29) + k31*x19/(k32 + x19)) + (-1)*k2*k33*x1)/k2),
  Eq(Derivative(x2, t), (1*k2*k51*x7*x3 + (-1)*k2*k52*x2 + (-1)*k2*k53*x2)/k2),
  Eq(Derivative(x3, t), ((-1)*k2*k51*x7*x3 + 1*k2*k52*x2 + 1*k2*k53*x2 + 1*k2*k55*(1 - x9**k56/(k57**k56 + x9**k56)) + (-1)*k2*k58*x3)/k2),
  Eq(Derivative(x4, t), (1*k2*k53*x2 + (-1)*k2*x4*k54*(1 + 6/125*x4/x3/(1 + x4/x3)) + (-1)*k2*k59*x4/x3*x3)/k2),
  Eq(Derivative(x5, t), (1*k2*k66*x6/(k67 + x6) + (-1)*k2*k68*x5)/k2),
  Eq(Derivative(x6, t), (1*k63*k72/(k62 + k72) + (-1)*k65*x6/(k64 + x6) + (-1)*k2*x5*k69*x6/(k70 + x6))/k2),
  Eq(Derivative(x7, t), ((-2)*k4*x8**k5/(k6**k5 + x8**k5)*x7 + 4*k48*x16 + 4*k49*x19 + (-1)*k2*k50*x7 + (-1)*k2*k51*x7*x3 + 1*k2*k52*x2 + 1*k2*x4*k54*(1 + 6/125*x4/x3/(1 + x4/x3)) + 1*k2*k59*x4/x3*x3 + 1*k2*x5*k69*x6/(k70 + x6))/k2),
  Eq(Derivative(x8, t), (1*k2*k11*(1 - x9**k12/(k13**k12 + x9**k12)) + (-1)*k2*k18*x1**k19/(k20**k19 + x1**k19)*x8)/k2),
  Eq(Derivative(x9, t), (1*k2*k14*(1 - x7**k15/(k16**k15 + x7**k15)) + (-1)*k2*k17*x9)/k2),
  Eq(Derivative(x10, t), 0),
  Eq(Derivative(x11, t), (1*k3*k7*x9**k8/(k9**k8 + x9**k8) + (-1)*k3*k10*x11 + (-1)*k3*k34*x13*x11 + 1*k3*k35*x14 + (-1)*k3*k36*k71*x11 + 1*k3*k37*x12 + 1*k48*x16)/k3),
  Eq(Derivative(x12, t), (1*k3*k36*k71*x11 + (-1)*k3*k37*x12 + (-1)*k3*k42*x12*k71 + 1*k3*k43*x16)/k3),
  Eq(Derivative(x13, t), ((-1)*k3*k21*x13 + 1*k3*k22 + (-1)*k3*k34*x13*x11 + 1*k3*k35*x14 + (-2)*k3*k38*x13**2*x20 + 2*k3*k39*x18 + (-1)*k3*k44*x14*x13 + 1*k3*k45*x17)/k3),
  Eq(Derivative(x14, t), (1*k3*k34*x13*x11 + (-1)*k3*k35*x14 + (-1)*k3*k44*x14*x13 + 1*k3*k45*x17)/k3),
  Eq(Derivative(x15, t), (1*k3*k40*k71*x20 + (-1)*k3*k41*x15 + (-1)*k3*k46*x15*k71 + 1*k3*k47*x19)/k3),
  Eq(Derivative(x16, t), (1*k3*k42*x12*k71 + (-1)*k3*k43*x16 + (-1)*k48*x16)/k3),
  Eq(Derivative(x17, t), (1*k3*k44*x14*x13 + (-1)*k3*k45*x17 + (-1)*k3*k60*x17)/k3),
  Eq(Derivative(x18, t), (1*k3*k38*x13**2*x20 + (-1)*k3*k39*x18 + (-1)*k3*k61*x18)/k3),
  Eq(Derivative(x19, t), (1*k3*k46*x15*k71 + (-1)*k3*k47*x19 + (-1)*k49*x19)/k3),
  Eq(Derivative(x20, t), (1*k3*k23 + (-1)*k3*k24*(1 - k71**k25/(k26**k25 + k71**k25))*x20 + (-1)*k3*k38*x13**2*x20 + 1*k3*k39*x18 + (-1)*k3*k40*k71*x20 + 1*k3*k41*x15 + 1*k49*x19)/k3),
  Eq(Derivative(x21, t), 0) ]