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Enzyme kinetics: the whole picture reveals hidden meanings
Author(s) -
Pinto Maria F.,
Estevinho Berta N.,
Crespo Rosa,
Rocha Fernando A.,
Damas Ana M.,
Martins Pedro M.
Publication year - 2015
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.13275
Subject(s) - formalism (music) , enzyme kinetics , michaelis–menten kinetics , kinetic energy , enzyme , kinetics , chemistry , computation , enzyme inhibition , algebraic number , enzyme catalysis , statistical physics , computational chemistry , combinatorial chemistry , biological system , computer science , mathematics , physics , enzyme assay , biochemistry , active site , biology , classical mechanics , algorithm , mathematical analysis , art , musical , visual arts
The methodology adopted by Michaelis and Menten in 1913 is still routinely used to characterize the catalytic power and selectivity of enzymes. These kinetic measurements must be performed soon after the purified enzyme is mixed with a large excess of substrate. Other time scales and solution compositions are no less physiologically relevant, but fall outside the range of applicability of the classical formalism. Here we show that the complete picture of an enzyme's mode of function is critically obscured by the limited scope of conventional kinetic analysis, even in the simplest case of a single active site without inhibition. This picture is now unveiled in a mathematically closed form that remains valid over the reaction time for all combinations of enzyme/substrate concentrations and rate constants. Algebraic simplicity is maintained in the new formalism when stationary reaction phases are considered. By achieving this century‐old objective, the otherwise hidden role of the reversible binding step is revealed and atypical kinetic profiles are explained. Most singular kinetic behaviors are identified in a critical region of conditions that coincide with typical cell conditions. Because it is not covered by the Michaelis–Menten model, the critical region has been missed until now by low‐ and high‐throughput screenings of new drugs. New possibilities are therefore raised for novel and once‐promising inhibitors to therapeutically target enzymes.