Transient-State Analysis of Porcine Dihydropyrimidine Dehydrogenase Reveals Reductive Activation by NADPH.

Biochemistry
Brett A BeaupreGraham R Moran

Abstract

Dihydropyrimidine dehydrogenase (DPD) catalyzes the initial step in the catabolism of the pyrimidines uracil and thymine. Crystal structures have revealed an elaborate subunit architecture consisting of two flavin cofactors, apparently linked by four Fe4S4 centers. Analysis of the DPD reaction(s) equilibrium position under anaerobic conditions revealed a reaction that favors dihydropyrimidine formation. Single-turnover analysis shows biphasic kinetics. The serine variant of the candidate general acid, cysteine 671, provided enhanced kinetic resolution for these phases. In the first event, one subunit of the DPD dimer takes up two electrons from NADPH in a reductive activation. Spectrophotometric deconvolution suggests that these electrons reside on one of the two flavins. The fact that oxidation of the enzyme by dioxygen can be suppressed by the addition of pyrimidine is consistent with these electrons residing on the FMN. The second phase involves further oxidation of NADPH and concomitant reduction of the pyrimidine substrate. During this phase no net reduction of DPD cofactors is observed, indicating that the entire cofactor set acts as a wire, transmitting electrons from NADPH to the pyrimidine rapidly. This indicates that ...Continue Reading

References

Jan 31, 1992·Biochemical and Biophysical Research Communications·B Podschun
Oct 20, 1989·European Journal of Biochemistry·B PodschunK D Schnackerz
Dec 1, 1993·Proceedings of the National Academy of Sciences of the United States of America·D P BaccanariT Spector
Dec 14, 1993·Biochemical Pharmacology·T SpectorD J Porter
Aug 1, 1996·Archives of Biochemistry and Biophysics·U SchmittK D Schnackerz
Jul 1, 1997·Protein Expression and Purification·K RosenbaumK D Schnackerz
Apr 9, 2001·Investigational New Drugs·J S de Bono, C J Twelves
May 2, 2003·Nature Reviews. Cancer·Daniel B LongleyPatrick G Johnston
Mar 30, 1957·Nature·C HEIDELBERGERJ SCHEINER
Jan 1, 1963·Experimental Cell Research·C HEIDELBERGER
Sep 29, 2004·Biochimica Et Biophysica Acta·Klaus D SchnackerzPaul F Cook
Jul 2, 2017·Archives of Biochemistry and Biophysics·Renata A G ReisM Cristina Nonato
Feb 24, 2020·Protein Expression and Purification·Brett A BeaupreGraham R Moran

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.