return (self.VmALD*(x[2] - (self.KeqTPI*x[13]**2)/(self.KeqALD*(1 + self.KeqTPI)**2)))/(self.KmALDF16P*(1 + x[2]/self.KmALDF16P + x[13]/((1 + self.KeqTPI)*self.KmALDDHAP) + (self.KeqTPI*x[13])/((1 + self.KeqTPI)*self.KmALDGAP) + (self.KeqTPI*x[2]*x[13])/((1 + self.KeqTPI)*self.KmALDF16P*self.KmALDGAPi) + (self.KeqTPI*x[13]**2)/((1 + self.KeqTPI)**2*self.KmALDDHAP*self.KmALDGAP)))