[ Eq(Derivative(x1, t), 1*k22*(k1 - k2*x1 - k3*x2**k13*x1/(k12**k13 + x2**k13) + (k4 + k5*x1**k7/(k6**k7 + x1**k7))*(x3 - x1) - (k8 + k9*k10**k11/(k10**k11 + x1**k11))*x1)/k22),
  Eq(Derivative(x2, t), 1*k22*((k14 + k15*(x1/200)**k17/((x1/200)**k17 + k16**k17))*(1 - x2) - (k18 + k19*k20**k21/(x2**k21 + k20**k21))*x2)/k22),
  Eq(Derivative(x3, t), 1*k22*(k1 - k2*x3 - k3*x2**k13*x3/(k12**k13 + x2**k13))/k22) ]