In order to develop a model system for studying drug metabolism, we constructed recombinant yeast strains expressing human liver cytochromes P450. A high yield of cDNA-derived CYP2D6 was obtained, due to optimization of the initiation ATG codon context. The PCR-based site-mutagenesis method was used to introduce an AAA sequence immediately before the initiation codon resulting in increased translation of the GAL10-CYC1-derived mRNA. The use of a peptidase-deficient yeast strain also helped to increase the CYP2D6 content. A P450 content of 250 +/- 30 pmol per mg of microsomal protein was achieved. HPLC analysis confirmed that heterologously expressed CYP2D6 catalysed the oxidation of debrisoquine and dextromethorphan, two prototype substrates for CYP2D6. The Km for debrisoquine 4-hydroxylase was found to be 50 microM and Vmax 7.5 pmol mg-1 min-1. Dextromethorphan O-demethylase activity in CYP2D6-containing microsomes was characterized by Km 8.5 microM and Vmax 700 pmol mg-1 min-1. Biotransformation of debrisoquine and dextromethorphan was not detected in control microsomes. Yeast synthesizing CYP2D6 represents a useful in vitro system for studying xenobiotic metabolism.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1097/00008571-199504000-00007 | DOI Listing |
Braz J Biol
January 2025
Escuela Superior Politécnica de Chimborazo - ESPOCH, El Coca, Ecuador.
The breeding and exploitation of chickens at the backyard or commercial family level is an activity of great economic relevance for families in Ecuador. In addition to providing protein of high biological value for food security, it revalues local food resources that could provide productive benefits. With this objective, a study has been conducted in order to explore the effect of C.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Chemical and Biomolecular Engineering, Lehigh University, 124 E. Morton Street, Bethlehem, Pennsylvania 18015, United States.
Quantum dot (QD) light-emitting diodes (QLEDs) are promising candidates for next-generation displays because of their high efficiency, brightness, broad color gamut, and solution-processability. Large-scale solution-processing of electroluminescent QLEDs poses significant challenges, particularly concerning the precise control of the active layer's thickness and uniformity. These obstacles directly impact charge transport, leading to current leakage and reduced overall efficiency.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
A ruthenium-catalyzed intramolecular cascade cyclization of allene-alkyne has been achieved. This method offers a streamlined and atom-economical approach for the construction of sulfone bearing 1-cyclopenta[]naphthalenes, an important structural scaffold that exists in biologically active compounds. Our approach, backed by mechanistic insights from deuterium labeling, DFT calculations, and potential for reaction scale-up, presents synthetic chemists with an invaluable tool for efficiently producing a distinct carbon framework in a one-pot manner.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, P. R. China.
Due to their strong aromaticity and difficulties in chemo-, regio-, and enantioselectivity control, asymmetric hydrogenation of naphthol derivatives to 1,2,3,4-tetrahydronaphthols has remained a long-standing challenge. Herein, we report the first example of homogeneous asymmetric hydrogenation of naphthol derivatives catalyzed by tethered rhodium-diamine catalysts, affording a wide array of optically pure 1,2,3,4-tetrahydronaphthols in high yields with excellent regio-, chemo-, and enantioselectivities (up to 98% yield and >99% ee). Mechanistic studies with experimental and computational approaches reveal that fluorinated solvent 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) plays vital roles in the control of reactivity and selectivity, and 1-naphthol is reduced via a cascade reaction pathway, including dearomative tautomerization, 1,4-hydride addition, and 1,2-hydride addition in sequence.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
BM Research Europe, Hartree Centre, Daresbury WA4 4AD, United Kingdom.
In this Letter, we study the phase transition between amorphous ices and the nature of the hysteresis cycle separating them. We discover that a topological transition takes place as the system transforms from low-density amorphous ice (LDA) at low pressures to high-density amorphous ice (HDA) at high pressures. Specifically, we uncover that the hydrogen bond network (HBN) displays qualitatively different topologies in the LDA and HDA phases: the former characterized by disentangled loop motifs, with the latter displaying topologically complex long-lived Hopf-linked and knotted configurations.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!