${\mathrm{K}}_{\mathrm{m}}$ value is defined as

${\mathrm{K}}_{\mathrm{m}}$ is Michaelis constant. It is a mathematical derivation or constant which indicates the substrate concentration at which the chemical reaction catalysed by an enzyme attains half its maximum velocity or we can say that the concentration of the substrate at which half the maximum velocity of the enzyme is attained is ${\mathrm{K}}_{\mathrm{m}}$.