function dxdt = michaelis_menten(t,x)
% USAGE: dxdt = michaelis_menten(t,x)
global k1 km1 k2 e0
dxdt = zeros(size(x));

s = x(1);

K = (km1+k2)/k1;

dxdt(1) = -k2*e0*s/(K+s);

return