[ Eq(Derivative(x1, t), ((-1)*k1*x1/(k2 + x1) + (-1)*k3*x1*x2/(k6 + k4*x2 + k5*x1 + x1*x2) + 1*k7*x3/(k8 + x3))/k10),
  Eq(Derivative(x2, t), (1*k1*x1/(k2 + x1) + (-1)*k3*x1*x2/(k6 + k4*x2 + k5*x1 + x1*x2))/k10),
  Eq(Derivative(x3, t), (2*k3*x1*x2/(k6 + k4*x2 + k5*x1 + x1*x2) + (-1)*k7*x3/(k8 + x3))/k10),
  Eq(Derivative(x4, t), (1*k7*x3/(k8 + x3) + (-1)*k9*x4)/k10),
  Eq(Derivative(x5, t), (-1)*k9*x4/k10),
  Eq(Derivative(x6, t), 0) ]