Question

The Michaelis-Menten equation models the hyperbolic relationship between [S] and the initial reaction rate V for an enzyme-catalyzed, single-substrate reaction E+S E S E+P. The model can be more readily understood when comparing three conditions: (S) <<K.. [S] = Km, and [S] >> Km. Match each statement with the condition that it describes. Note that "rate" refers to initial velocity V, where steady state conditions are assumed. Etotal) refers to the total enzyme concentration and Etree refers to the concentration of free enzyme. S] <<K. S = Km [S] >> Kin Not true for any of these conditions Answer Bank Almost all active sites are empty is equal to ES] Increasing will lower

Answer 1

1. (S) << Km - At low concentration fo substrate , velocity is proportional to substrate concentration , the enzyme catalyzed reaction is a first order reaction.

So , the rate is directly proportional to (S).

2. (S) = km , (Efree) = (ES) .

3. (S) >> Km - At high (S) , the velocity become virtually independent of (S) and approaches a maximal limit. Since rate is no longer dependent on (S) at high concentration the enzyme catalyzed reaction obeys zero order kinetics.

So ,Reaction is independent of (S) , (ES) is much higher than (Efree) .

4. Not true for any of these conditions - increasing Etotal will lose km beacuse Km shows the affinity of the enzes towards a particular substrate , it is the intrinsic property if an enzyme that do not depend on the concentration of enzyme instead depends on the binding of enzyme to the substrate .