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In vivo enzyme levels are governed by the rates of de novo enzyme synthesis and degradation. A current lack of consensus on values of the in vivo turnover half-lives of human cytochrome P450 (CYP) enzymes places a significant limitation on the accurate prediction of changes in drug concentration-time profiles associated with interactions involving enzyme(More)
The complete denaturation and subsequent renaturation and reconstitution of a polytopic integral membrane protein are demonstrated. Delipidated bacteriorhodopsin (Huang, K.-S., Bayley, H., and Khorana, H. G. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 323-327) is completely denatured when transferred into 88% formic acid or anhydrous trifluoroacetic acid as(More)
Interferon-alpha (IFN-alpha) subtypes were separated by HPLC from the IFN mixtures produced by virus-stimulated human lymphoblastoid cells and leukocytes. Together with preparations of lymphoblastoid IFN and recombinant IFN-beta, these were tested in three human tumor cell lines derived from liver, lung, and neuroblasts. Their relative antiviral activities(More)
The previously described chymotryptic fragment of bacteriorhodopsin, C-2 (amino acids 1-71), is cleaved by 70% formic acid to two fragments, A-1 (amino acids 1-36) and A-2 (amino acids 37-71), which have been separated by high pressure liquid chromatography. The fragments A-1 and A-2, separately or together, are not able to replace C-2 in forming a stable(More)
Carbamazepine (CBZ) is a widely prescribed anticonvulsant whose use is often associated with idiosyncratic hypersensitivity. Sera of CBZ-hypersensitive patients often contain anti-CYP3A antibodies, including those to a CYP3A23 K-helix peptide that is also modified during peroxidative CYP3A4 heme-fragmentation. We explored the possibility that cytochromes(More)
Fasiglifam (TAK-875), a Free Fatty Acid Receptor 1 (FFAR1) agonist in development for the treatment of type 2 diabetes, was voluntarily terminated in phase 3 due to adverse liver effects. A mechanistic investigation described in this manuscript focused on the inhibition of bile acid (BA) transporters as a driver of the liver findings. TAK-875 was an in(More)
The monotopic, endoplasmic reticulum (ER)-anchored cytochromes P450 (P450s) undergo variable proteolytic turnover. CYP3A4, the dominant human liver drug-metabolizing enzyme, is degraded via a ubiquitin (Ub)-dependent 26S proteasomal pathway after heterologous expression in Saccharomyces cerevisiae. This turnover involves the Ub-conjugating enzyme Ubc7p and(More)
Ca2+-induced transformation of phosphatidylcholine-phosphatidic acid vesicles to larger bilayer structures has been examined using nuclear magnetic resonance, electron microscopy, gel permeation and radioisotope tracer techniques. For concentrated vesicle preparations where phosphatidic acid content remains less than 50% of total lipid, transformation to(More)
HIV-host infection systems in vitro are important in the pre-clinical assessment of anti-retroviral drug activity. The present report describes the development of a new HIV-host model comprised of an epithelial cell line of HeLa lineage (HeLa-1), transfected with expression vectors bearing tat and rev (TART) genes of HIV-1 as well as the CD4 receptor gene,(More)