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The Interaction of Porcine Dihydropyrimidine Dehydrogenase with the Chemotherapy Sensitizer: 5-Ethynyluracil.
Biochemistry. 2021 04 13; 60(14):1120-1132.B

Abstract

Dihydropyrimidine dehydrogenase (DPD) is a complex enzyme that reduces the 5,6-vinylic bond of pyrimidines, uracil, and thymine. 5-Fluorouracil (5FU) is also a substrate for DPD and a common chemotherapeutic agent used to treat numerous cancers. The reduction of 5FU to 5-fluoro-5,6-dihydrouracil negates its toxicity and efficacy. Patients with high DPD activity levels typically have poor outcomes when treated with 5FU. DPD is thus a central mitigating factor in the treatment of a variety of cancers. 5-Ethynyluracil (5EU) covalently inactivates DPD by cross-linking with the active-site general acid cysteine in the pyrimidine binding site. This reaction is dependent on the simultaneous binding of 5EU and nicotinamide adenine dinucleotide phosphate (NADPH). This ternary complex induces DPD to become activated by taking up two electrons from the NADPH. The covalent inactivation of DPD by 5EU occurs concomitantly with this reductive activation with a rate constant of ∼0.2 s-1. This kinact value is correlated with the rate of reduction of one of the two flavin cofactors and the localization of a mobile loop in the pyrimidine active site that places the cysteine that serves as the general acid in catalysis proximal to the 5EU ethynyl group. Efficient cross-linking is reliant on enzyme activation, but this process appears to also have a conformational aspect in that nonreductive NADPH analogues can also induce a partial inactivation. Cross-linking then renders DPD inactive by severing the proton-coupled electron transfer mechanism that transmits electrons 56 Å across the protein.

Authors+Show Affiliations

Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States.Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States.Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States.Synchrotron Research Center, Life Sciences Collaborative Access Team, Northwestern University, Argonne, Illinois 60439, United States.Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States.Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

33755421

Citation

Forouzesh, Dariush C., et al. "The Interaction of Porcine Dihydropyrimidine Dehydrogenase With the Chemotherapy Sensitizer: 5-Ethynyluracil." Biochemistry, vol. 60, no. 14, 2021, pp. 1120-1132.
Forouzesh DC, Beaupre BA, Butrin A, et al. The Interaction of Porcine Dihydropyrimidine Dehydrogenase with the Chemotherapy Sensitizer: 5-Ethynyluracil. Biochemistry. 2021;60(14):1120-1132.
Forouzesh, D. C., Beaupre, B. A., Butrin, A., Wawrzak, Z., Liu, D., & Moran, G. R. (2021). The Interaction of Porcine Dihydropyrimidine Dehydrogenase with the Chemotherapy Sensitizer: 5-Ethynyluracil. Biochemistry, 60(14), 1120-1132. https://doi.org/10.1021/acs.biochem.1c00096
Forouzesh DC, et al. The Interaction of Porcine Dihydropyrimidine Dehydrogenase With the Chemotherapy Sensitizer: 5-Ethynyluracil. Biochemistry. 2021 04 13;60(14):1120-1132. PubMed PMID: 33755421.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The Interaction of Porcine Dihydropyrimidine Dehydrogenase with the Chemotherapy Sensitizer: 5-Ethynyluracil. AU - Forouzesh,Dariush C, AU - Beaupre,Brett A, AU - Butrin,Arseniy, AU - Wawrzak,Zdzislaw, AU - Liu,Dali, AU - Moran,Graham R, Y1 - 2021/03/23/ PY - 2021/3/24/pubmed PY - 2021/9/10/medline PY - 2021/3/23/entrez SP - 1120 EP - 1132 JF - Biochemistry JO - Biochemistry VL - 60 IS - 14 N2 - Dihydropyrimidine dehydrogenase (DPD) is a complex enzyme that reduces the 5,6-vinylic bond of pyrimidines, uracil, and thymine. 5-Fluorouracil (5FU) is also a substrate for DPD and a common chemotherapeutic agent used to treat numerous cancers. The reduction of 5FU to 5-fluoro-5,6-dihydrouracil negates its toxicity and efficacy. Patients with high DPD activity levels typically have poor outcomes when treated with 5FU. DPD is thus a central mitigating factor in the treatment of a variety of cancers. 5-Ethynyluracil (5EU) covalently inactivates DPD by cross-linking with the active-site general acid cysteine in the pyrimidine binding site. This reaction is dependent on the simultaneous binding of 5EU and nicotinamide adenine dinucleotide phosphate (NADPH). This ternary complex induces DPD to become activated by taking up two electrons from the NADPH. The covalent inactivation of DPD by 5EU occurs concomitantly with this reductive activation with a rate constant of ∼0.2 s-1. This kinact value is correlated with the rate of reduction of one of the two flavin cofactors and the localization of a mobile loop in the pyrimidine active site that places the cysteine that serves as the general acid in catalysis proximal to the 5EU ethynyl group. Efficient cross-linking is reliant on enzyme activation, but this process appears to also have a conformational aspect in that nonreductive NADPH analogues can also induce a partial inactivation. Cross-linking then renders DPD inactive by severing the proton-coupled electron transfer mechanism that transmits electrons 56 Å across the protein. SN - 1520-4995 UR - https://www.unboundmedicine.com/medline/citation/33755421/The_Interaction_of_Porcine_Dihydropyrimidine_Dehydrogenase_with_the_Chemotherapy_Sensitizer:_5_Ethynyluracil_ L2 - https://doi.org/10.1021/acs.biochem.1c00096 DB - PRIME DP - Unbound Medicine ER -