function dxdt = michaelis_menten(t,x) % USAGE: dxdt = michaelis_menten(t,x) global k1 km1 k2 e0 % global allows program to define constants % says "I want those variables available to any function that might need it" dxdt = zeros(size(x)); s = x(1); K = (km1+k2)/k1; dxdt(1) = -k2*e0*s/(K+s); dxdt(2) = -dxdt return