@misc{10481/64954,
year = {2020},
month = {8},
url = {http://hdl.handle.net/10481/64954},
abstract = {Human NQO1 [NAD(H):quinone oxidoreductase 1] is a multi-functional and stress-inducible
dimeric protein involved in the antioxidant defense, the activation of cancer prodrugs and the stabilization
of oncosuppressors. Despite its roles in human diseases, such as cancer and neurological disorders,
a detailed characterization of its enzymatic cycle is still lacking. In this work, we provide a
comprehensive analysis of the NQO1 catalytic cycle using rapid mixing techniques, including
multiwavelength and spectral deconvolution studies, kinetic modeling and temperature-dependent
kinetic isotope e ects (KIEs). Our results systematically support the existence of two pathways for
hydride transfer throughout the NQO1 catalytic cycle, likely reflecting that the two active sites in the
dimer catalyze two-electron reduction with di erent rates, consistent with the cooperative binding of
inhibitors such as dicoumarol. This negative cooperativity in NQO1 redox activity represents a sort
of half-of-sites activity. Analysis of KIEs and their temperature dependence also show significantly
di erent contributions from quantum tunneling, structural dynamics and reorganizations to catalysis
at the two active sites. Our work will improve our understanding of the e ects of cancer-associated
single amino acid variants and post-translational modifications in this protein of high relevance in
cancer progression and treatment.},
organization = {ERDF/Spanish Ministry of Science, Innovation and Universities-State Research Agency 	
RTI2018-096246-B-I00},
organization = {Spanish Ministry of Science and Innovation-State Research Agency 	
PID2019-103901GB-I00},
organization = {Junta de Andalucía

P11-CTS-07187
P18-RT-2413},
organization = {Gobierno de Aragón-FEDER 	
E35_20R},
publisher = {Mdpi},
keywords = {Antioxidant enzymes},
keywords = {Antioxidant response},
keywords = {Cancer},
keywords = {Oxidoreductases},
keywords = {Enzyme kinetic analysis},
keywords = {Functional cooperativity},
keywords = {Hydride transfer},
keywords = {Kinetic isotope effects},
keywords = {Quantum tunneling},
keywords = {Conformational dynamics},
title = {The Catalytic Cycle of the Antioxidant and Cancer-Associated Human NQO1 Enzyme: Hydride Transfer, Conformational Dynamics and Functional Cooperativity},
doi = {10.3390/antiox9090772},
author = {Anoz Carbonell, Ernesto and Timson, David J. and Pey Rodríguez, Ángel Luis and Medina, Milagros},
}