Definition of Michaelis constant in English:

Michaelis constant


  • The concentration of a given substrate which catalyses the associated reaction at half the maximum rate.

    • ‘In such a model, the locus q controls the activity of enzyme q, and qi depends on the maximal velocity and on the Michaelis constant of enzyme q in individual i.’
    • ‘Historically, it was observed that selenate and sulphate competed for influx to roots, and exhibited similar Michaelis constants for high-affinity transport.’
    • ‘Although this residue appears to be absolutely conserved, its replacement by the less bulky alanine or the more bulky cystein has relatively little influence on the catalytic rate and the Michaelis constant of the enzyme.’
    • ‘The JHEs did not differ in any biochemical characteristic such as Michaelis constant, inhibition, or thermostability.’
    • ‘This result is different from the previous one where at least two sets of Michaelis constants were needed to fit the hydrolysis kinetics.’


1930s: named after Leonor Michaelis (1875–1949), German-born American chemist.


Michaelis constant