Conformational Nonequilibrium Enzyme Kinetics: Generalized Michaelis–Menten Equation
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Cao_Orig Man_Conformational Nonequilibrium.pdf
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Author(s)
Piephoff, Daniel Evan
Wu, Jianlan
Cao, Jianshu
Date Issued
July 2017
Journal
The Journal of Physical Chemistry Letters
Publisher
American Chemical Society (ACS)
Citation
Piephoff, D. Evan et al. “Conformational Nonequilibrium Enzyme Kinetics: Generalized Michaelis–Menten Equation.” The Journal of Physical Chemistry Letters 8, 15 (July 2017): 3619–3623 © 2017 American Chemical Society
Version
Original manuscript
Abstract
In a conformational nonequilibrium steady state (cNESS), enzyme turnover is modulated by the underlying conformational dynamics. On the basis of a discrete kinetic network model, we use an integrated probability flux balance method to derive the cNESS turnover rate for a conformation-modulated enzymatic reaction. The traditional Michaelis-Menten (MM) rate equation is extended to a generalized form, which includes non-MM corrections induced by conformational population currents within combined cyclic kinetic loops. When conformational detailed balance is satisfied, the turnover rate reduces to the MM functional form, explaining its general validity. For the first time, a one-to-one correspondence is established between non-MM terms and combined cyclic loops with unbalanced conformational currents. Cooperativity resulting from nonequilibrium conformational dynamics can be achieved in enzymatic reactions, and we provide a novel, rigorous means of predicting and characterizing such behavior. Our generalized MM equation affords a systematic approach for exploring cNESS enzyme kinetics.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1021/ACS.JPCLETT.7B01210
