A Quasi-Michaelis-Menten Mechanism Explains the Nonlinear Relationship between Transition Metals and PM2.5 Oxidative Potential Measured by the Dithiothreitol (DTT) Assay.
4 affiliations
- 1Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong999077, China.
- 2Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong999077, China.
- 3Institution of Atmospheric Environment, Jiangsu Provincial Academy of Environmental Science, Nanjing, Jiangsu210036, China.
- 4School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong266237, China.
Abstract
Oxidative potential (OP), defined as the capacity of particulate matter (PM) to consume antioxidants and/or generate reactive oxygen species, is increasingly used as a metric for assessing PM toxicity. However, the concentration-response relationship between PM components and OP measured by the dithiothreitol (DTT) assay (OPDTT) is often nonlinear, and the underlying mechanism remains poorly understood. Here, we measured OPDTT of laboratory-prepared solutions and ambient PM2.5 samples and propose a quasi-Michaelis-Menten mechanism involving DTT, transition metals, and oxygen. The derived equations for copper (Cu) and manganese (Mn) quantitatively reproduced the nonlinear OPDTT response observed in both single-metal standard solutions and ambient samples, as well as the antagonistic effects of Cu-Mn mixtures. For 62 ambient PM2.5 samples collected in Beijing over one year, a model based on water-soluble Cu, Mn, and water-soluble organic carbon (WSOC), assuming a linear WSOC contribution, accounted for 98.6% of the measured OPDTT. These results support the proposed quasi-Michaelis-Menten mechanism as an explanation for the nonlinear concentration-response relationship and provide a basis for predicting OPDTT from PM2.5 chemical composition.
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BibTeX
@article{chen2026quasimichaelismenten,
title = {{A Quasi-Michaelis-Menten Mechanism Explains the Nonlinear Relationship between Transition Metals and PM2.5 Oxidative Potential Measured by the Dithiothreitol (DTT) Assay.}},
author = {Hanzhe Chen and Yuhuang Cheng and Kezheng Liao and Manfei Lin and Tao Li and Jian Zhen Yu},
journal = {Environmental science \& technology},
year = {2026},
month = oct,
doi = {10.1021/acs.est.6c09293},
url = {https://europepmc.org/article/MED/42916991},
note = {CC BY},
}
RIS
TY - JOUR
TI - A Quasi-Michaelis-Menten Mechanism Explains the Nonlinear Relationship between Transition Metals and PM2.5 Oxidative Potential Measured by the Dithiothreitol (DTT) Assay.
AU - Hanzhe Chen
AU - Yuhuang Cheng
AU - Kezheng Liao
AU - Manfei Lin
AU - Tao Li
AU - Jian Zhen Yu
PY - 2026
DA - 2026/10/01
JO - Environmental science & technology
DO - 10.1021/acs.est.6c09293
UR - https://europepmc.org/article/MED/42916991
AB - Oxidative potential (OP), defined as the capacity of particulate matter (PM) to consume antioxidants and/or generate reactive oxygen species, is increasingly used as a metric for assessing PM toxicity. However, the concentration-response relationship between PM components and OP measured by the dithiothreitol (DTT) assay (OPDTT) is often nonlinear, and the underlying mechanism remains poorly understood. Here, we measured OPDTT of laboratory-prepared solutions and ambient PM2.5 samples and propose a quasi-Michaelis-Menten mechanism involving DTT, transition metals, and oxygen. The derived equations for copper (Cu) and manganese (Mn) quantitatively reproduced the nonlinear OPDTT response observed in both single-metal standard solutions and ambient samples, as well as the antagonistic effects of Cu-Mn mixtures. For 62 ambient PM2.5 samples collected in Beijing over one year, a model based on water-soluble Cu, Mn, and water-soluble organic carbon (WSOC), assuming a linear WSOC contribution, accounted for 98.6% of the measured OPDTT. These results support the proposed quasi-Michaelis-Menten mechanism as an explanation for the nonlinear concentration-response relationship and provide a basis for predicting OPDTT from PM2.5 chemical composition.
SN - 0013-936X
SN - 1520-5851
ER -