Explain everything about steady state and rapid equilibrium method.

Km is defined in 2 ways -
1) Concentration of substrate at which half of the active sites are files
 2) It is related to the rate constants of the individual steps in the catalytic scheme shown
E+S→ES (k1 is the rate constant for this reaction)
ES→E+S (K2 is the rate of this reaction... note this is just a reversible reaction)
ES→E+P (k3 is the rate constant for this reaction)
Now we know that:-
Km= (K2 + k3)/k1
n other words, Km is dissociation constant of ES complex if k3 is much smaller than K2
Therefore Km=k2/k1
Now from the above formula of Km, we can easily say that if Km value is higher than ES complex Breaks easily so that why high Km indicates low affinity i.e. enzymes do not bind substrate for a long time.
 if we consider low Km value then ES complex
Do not break easily so that why enzyme now binds substrate for a long time and thus it is said that when Km is low then enzyme has a higher affinity for substrate. https://en.wikipedia.org/wiki/Enzyme_kinetics
http://plantphys.info/plant_physiology/enzymekinetics.shtml