[ Eq(Derivative(x1, t), (1*k1*k2*k3**k4/(k3**k4 + x4**k4) + (-1)*k1*k6*x1 + (-1)*k1*k44*x1/(k45 + x1))/k1),
  Eq(Derivative(x2, t), (1*k1*k5*x1 + (-1)*k1*k7*x2/(k8 + x2) + (-1)*k1*(k9*x2 - k10*x4) + (-1)*k1*k58*x2 + 1*k1*k69*x3/(k70 + x3))/k1),
  Eq(Derivative(x3, t), (1*k1*k7*x2/(k8 + x2) + (-1)*k1*k34*x3 + (-1)*k1*k59*x3/(k60 + x3) + (-1)*k1*k69*x3/(k70 + x3))/k1),
  Eq(Derivative(x4, t), (1*k1*(k9*x2 - k10*x4) + (-1)*k1*(k42*x13*x4 - k43*x16) + (-1)*k1*k61*x4/(k62 + x4) + (-1)*k1*k68*x4 + 1*k1*k71*x14/(k72 + x14))/k1),
  Eq(Derivative(x5, t), (1*k1*k11*x6 + (-1)*k1*k13*x5/(k14 + x5) + (-1)*k1*(k25*x5*x9 - k26*x11) + (-1)*k1*k51*x5 + 1*k1*k73*x7/(k74 + x7))/k1),
  Eq(Derivative(x6, t), ((-1)*k1*k12*x6 + 1*k1*k36*x4**k37/(k38**k37 + x4**k37) + (-1)*k1*k46*x6/(k47 + x6))/k1),
  Eq(Derivative(x7, t), (1*k1*k13*x5/(k14 + x5) + (-1)*k1*k15*x7/(k16 + x7) + (-1)*k1*k53*x7 + (-1)*k1*k73*x7/(k74 + x7))/k1),
  Eq(Derivative(x8, t), (1*k1*k17*x4**k18/(k19**k18 + x4**k18) + (-1)*k1*k41*x8 + (-1)*k1*k48*x8/(k49 + x8))/k1),
  Eq(Derivative(x9, t), (1*k1*k20*x8 + (-1)*k1*k23*x9/(k24 + x9) + (-1)*k1*(k25*x5*x9 - k26*x11) + (-1)*k1*k50*x9 + 1*k1*k75*x10/(k76 + x10))/k1),
  Eq(Derivative(x10, t), ((-1)*k1*k21*x10/(k22 + x10) + 1*k1*k23*x9/(k24 + x9) + (-1)*k1*k52*x10 + (-1)*k1*k75*x10/(k76 + x10))/k1),
  Eq(Derivative(x11, t), (1*k1*(k25*x5*x9 - k26*x11) + (-1)*k1*k27*x11/(k28 + x11) + (-1)*k1*(k31*x11 - k32*x13) + (-1)*k1*k55*x11 + 1*k1*k80*x12/(k81 + x12))/k1),
  Eq(Derivative(x12, t), (1*k1*k27*x11/(k28 + x11) + (-1)*k1*k29*x12/(k30 + x12) + (-1)*k1*k54*x12 + (-1)*k1*k80*x12/(k81 + x12))/k1),
  Eq(Derivative(x13, t), (1*k1*(k31*x11 - k32*x13) + (-1)*k1*k39*x13/(k40 + x13) + (-1)*k1*(k42*x13*x4 - k43*x16) + 1*k1*k77*x15/(k78 + x15) + (-1)*k1*k79*x13)/k1),
  Eq(Derivative(x14, t), ((-1)*k1*k35*x14 + 1*k1*k61*x4/(k62 + x4) + (-1)*k1*k63*x14/(k64 + x14) + (-1)*k1*k71*x14/(k72 + x14))/k1),
  Eq(Derivative(x15, t), ((-1)*k1*k33*x15 + 1*k1*k39*x13/(k40 + x13) + (-1)*k1*k56*x15/(k57 + x15) + (-1)*k1*k77*x15/(k78 + x15))/k1),
  Eq(Derivative(x16, t), (1*k1*(k42*x13*x4 - k43*x16) + (-1)*k1*k65*x16 + (-1)*k1*k66*x16/(k67 + x16))/k1) ]