function xprime=model(t,x);
ks=0.002; ksd1=0.001; ksd2=0.05; 
k1=10; k3=10; vm1=1; km1=0.02; kmr1=0.02; k2=0.1; 
k2a=0.01; km2=1; km2a=0.001; vm3=0.1; km3=0.02; kmr3=0.02; 
k4=1; k4a=1; vm4=1; km4=0.02; 
kmr4=0.1; eps=0.1; 
sig=x(1); S2=x(2); G2=x(3); C2=x(4); A2=x(5);
S1 = 1 - S2;;
C1 = 1 - C2;
A1 = 1 - A2;
xprime(1)=ks-ksd1*sig-ksd2*C2*sig; 
xprime(2)=(eps^-2)*((k1*sig*S1/(km1+S1))-(vm1*S2/(kmr1+S2)));
xprime(3)=(eps^-3)*(k2*S2+k2a*C2-km2*G2-km2a*C2*G2);
xprime(4)=(eps^-1)*((k3*G2*C1/(km3+C1))-(vm3*C2/(kmr3+C2)));
xprime(5)=(eps^2)*((k4*G2*A1/(km4+A1))+(k4a*C2*A1/(km4+A1))-(vm4*A2/(kmr4+A2)));
xprime=xprime';
end