A general explanation of the velocity and gross mechanism of enzyme-catalysed reactions. First stated in 1913, the hypothesis assumes that a complex is formed between an enzyme and its substrate, which complex then decomposes to yield free enzyme and the reaction product, the latter rate determine the overall rate of substrate-product conversion. The velocity of such a reaction is greatest when all the sites at which catalytic activity can take place on the enzyme molecules (active sites) are filled with substrate; i.e., when the substrate concentration is very high. These relationships provide the basis for all kinetic studies of enzymes and also have been applied to investigations of the effects of carriers upon the transport of substances through cell membranes.
The Michaelis-Menten mechanism for the catalysis of biological chemical reactions is one of the most important chemical reaction mechanisms in biochemistry.