Simple

From BioNetWiki

begin model 
begin parameters
   # Physical and geometric constants
   NA     6.0e23 #Avogadro’s num
   f	    0.01 #scaling factor
   Vo      f*1e-10 # L
   V       f*3e-12 # L
 
  # Initial concentrations
   EGF_conc 2e-9 # nM
   EGF0   EGF_conc*NA*Vo #nM
   EGFR0  f*1.8e5    #copy per cell

   # Rate constants 
   kp1    9.0e7/(NA*Vo) #input /M/sec         
   km1   0.06         #/sec    
end parameters

begin molecule types
   EGF(R)
   EGFR(L,CR1,Y1068~U~P)
end molecule types

begin seed species
   EGF(R)              EGF0
   EGFR(L,CR1,Y1068~U) EGFR0
end seed species

begin reaction rules
   EGF(R) + EGFR(L) <-> EGF(R!1).EGFR(L!1) kp1, km1
end reaction rules

begin observables
 # Species LR EGF(R!1).EGFR(L!1)
  Molecules Lbound EGF(R!+)
end observables
end model

begin actions
  generate_network({overwrite=>1});
  saveConcentrations();
  simulate_ode({suffix=>ode,n_steps=>20,t_end=>100});
#  resetConcentrations();
#  simulate_nf({suffix=>ssa,n_steps=>20,t_end=>100});
end actions