Km of an enzyme is
Km is the concentration of substrate which permits the enzyme to achieve half Vmax. An enzyme with a high Km has a low affinity for its substrate and requires a greater concentration of substrate to achieve Vmax. Increasing the substrate concentration indefinitely does not increase the rate of an enzyme-catalyzed reaction beyond a ceain point. This point is reached when there are enough substrate molecules to completely fill (saturate) the enzyme&;s active sites. The maximal velocity, or Vmax, is the rate of the reaction under these conditions. Vmax reflects how fast the enzyme can catalyze the reaction.
Dissociation constant
The normal physiological substrate concentration
The substrate concentration at half maximum velocity
Numerically identical for all isozymes that catalyze a given reaction
Enzymes