dx1/dt=-x1*k2-NGF0*k1*(x1-k3TrkA0);
dx2/dt=-x2*k5-(x2-k6Ras0)*(k4+(x1*sK^n)/(x5^n+sK^n));
dx3/dt=x2*(k8Raf0-x3)-k7*x3;
dx4/dt=x3*(k10Mek0-x4)-k9*x4;
dx5/dt=-k11*x5-x4*(x5-sErk0);
y1=x5;
x1(0)=0;
x2(0)=(k4*k6Ras0)/(k4+k5);
x3(0)=(k4*k6Ras0*k8Raf0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5)));
x4(0)=(k4*k6Ras0*k8Raf0*k10Mek0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5))*(k9+(k4*k6Ras0*k8Raf0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5)))));
x5(0)=(k4*k6Ras0*k8Raf0*k10Mek0*sErk0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5))*(k11+(k4*k6Ras0*k8Raf0*k10Mek0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5))*(k9+(k4*k6Ras0*k8Raf0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5))))))*(k9+(k4*k6Ras0*k8Raf0)/((k4+k5)*(k7+(k4*k6Ras0)/(k4+k5)))))
