  Michaelis-Menten equation is a basic equation of enzyme kinetics and gives an
acceptable approximation of real chemical reaction processes. Analyzing the
derivation of this equation yields the fact that its good performance of
approximating real reaction processes is due to Michaelis-Menten curve (15).
This curve is derived from Quasi-Steady-State Assumption(QSSA), which has been
proved always true and called Quasi-Steady-State Law by Banghe Li et al [19].
  Here, we found a quartic equation A(S,E)=0 (22), which gives more accurate
approximation of the reaction process in two aspects: during the quasi-steady
state of a reaction, Michaelis-Menten curve approximates the reaction well,
while our quartic equation $A(S,E)=0$ gives better approximation; near the end
of the reaction, our equation approaches the end of the reaction with a tangent
line same to that of the reaction, while Michaelis-Menten curve does not. In
addition, our quartic equation A(S,E)=0 differs to Michaelis-Menten curve less
than the order of $1/S^3$ as S approaches $+\infty$.
  By considering the above merits of A(S,E)=0, we suggest it as a replacement
of Michaelis-Menten curve. Intuitively, this new equation is more complex and
harder to understand. But, just because its complexity, it provides more
information about the rate constants than Michaelis-Menten curve does.
  Finally, we get a better replacement of the Michaelis-Menten equation by
combing A(S,E)=0 and the equation $dP/dt=k_2C(t)$.
