Michaelis constant is the substrate concentration at which the reaction velocity is equal to half the maximal velocity of the reaction.
Km = Michaelis constant
Km = the value of substrate concentration[S] that causes V= ½ Vmax *
The units of Km are M, concentration.
Velocity is related to Km through the Michaelis & Menten equation: v = (Vmax [S])/(Km + [S]).
- Vmax = maximum rate of reaction achievable for the enzyme under given conditions, only occurs at infinite substrate concentration.
[S] = substrate concentration.
A reaction with a low Michaelis constant value indicates a low binding affinity, where as a large value indicates a high binding affinity.
Michaelis, L ; Menten, M L ; Johnson, K A ; Goody, R S. The original Michaelis constant: translation of the 1913 Michaelis-Menten paper,
Biochemistry, 04 October 2011, Vol.50(39), pp.8264-9