# File gprotein_pathway.ode
# Model of G-protein signalling pathway 
# Figure 6.5

#G and L rescaled from text G->G/1000, L->L*10^9

#kinetic parameters
par krl=0.002
par krlm=0.01
par kg1=1
par kga=1
par kgd1=0.11

#concentration totals
par gt=1000
par rt=4000

#conservations
gbg=gt-g
gd=gt-g-ga
r=rt-rl

#set time-varying profile for ligand level
lt=(heav(t-100.001) - heav(t-700.001))

#dynamics
rl' = krl*lt*r - krlm*rl
g' = -kga*rl*g + kg1*gd*gbg
ga' = kga*rl*g - kgd1*ga

aux prob=kg1*gd*gbg
aux probgd=gd
aux probbgb=gbg
# initial condition
init rl=0, g=100, ga=0

# final time
@ total=1200
@ maxstor=100000000
@ bound=100000000
@ dt=0.0005
# set the plotting window size:
@ xlo=0, xhi=1200, ylo=0, yhi=700

# run the simulation in the GUI by selecting (I)nitialconds|(G)o
# plot species Ga by selecting (G)raphic stuff|(A)dd curve and 
# assigning the y-axis

done