Reactions	forward	backward
E + R + R <--> ER2
ER2 + S + S <--> ER2S2
ER2S2 <--> P + E

Inital Time	Final Time	Number of Time Steps	Skip	Integration Option
				Euler Euler Modified Fourth Order Runge-Kutta Adaptive Runge-Kutta BDF order 2 LSODES