Showing papers by "Jeroen Buters published in 1997"
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TL;DR: Results identify residues β270 and β364 as important modulators of paclitaxel’s interaction with tubulin as well as acquired mutations in the M40 isotype at nucleotide 810 (T → G; Phe270 → Val) in 1A9PTX10 cells and nucleotide 1092 (G → A; Ala364 → Thr) in1A 9PTX22 cells.
708 citations
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TL;DR: Data indicate that flavonoids enhance activity by increasing the pool of active P450 molecules within this P450 macrosystem by expanding the population of active receptor molecules.
131 citations
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TL;DR: The results suggest that the best CYP2A6 catalytic activity depends on properly posttranslationally modified proteins accumulating in a right ratio as a result of primary, secondary, and possibly tertiary infection of both viruses.
Abstract: Heterologous expression using baculovirus vectors has become a popular method for the production of catalytically active cytochrome P450s (CYPs). We have systematically optimized the multiplicity of infection (MOI) for a coinfection approach for the coexpression of CYP2A6 (viral vector designated v2A6) and NADPH-P450 oxidoreductase (OR; viral vector designated vOR) using Sf9 insect cells. A 3000-fold range of MOI was examined in stationary culture and stirred suspension culture. Surprisingly, our results indicate that the best CYP2A6 catalytic activity (850-1300 pmol/ min/mg total lysate protein as measured by coumarin 7-hydroxylase activity) was obtained only when using a low MOI of v2A6 (1.5-3 x 10(-2)) and a vOR of 10- to 20-fold less. This activity was approximately 7- to 11-fold higher than the best activity obtained when infecting cells with v2A6 alone. At this level of coinfection, the P450 content ranged from 180 to 250 pmol/mg total lysate protein, and the NADPH cytochrome c reductase activity ranged from 350 to 520 nmol/min/mg total lysate protein. Increasing the MOI of both viruses to 50-fold higher resulted in lower overall activity with the optimum (250 pmol/min/mg total lysate protein) being seen earlier postinfection (60 vs. 72 hr). Increasing the MOI of vOR to levels comparable with those of v2A6, decreased coumarin 7-hydroxylase activity 14-fold. These results suggest that the best CYP2A6 catalytic activity depends on properly posttranslationally modified proteins accumulating in a right ratio as a result of primary, secondary, and possibly tertiary infection of both viruses. These results also suggest that high OR expression results in degradation of P450.
48 citations
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TL;DR: The toxicity of TCDD in mammals including humans of different age and/or body weight can be predicted if their total body fat content is known, and predicted LD50 values of T CDD in these animals and humans are presented.
26 citations