دورية أكاديمية
Selective biotransformation of taxol to 6 alpha-hydroxytaxol by human cytochrome P450 2C8.
| العنوان: | Selective biotransformation of taxol to 6 alpha-hydroxytaxol by human cytochrome P450 2C8. |
|---|---|
| المؤلفون: | Rahman A; Division of Biopharmaceutics, United States Food and Drug Administration, Rockville, Maryland 20857., Korzekwa KR, Grogan J, Gonzalez FJ, Harris JW |
| المصدر: | Cancer research [Cancer Res] 1994 Nov 01; Vol. 54 (21), pp. 5543-6. |
| نوع المنشور: | Journal Article |
| اللغة: | English |
| بيانات الدورية: | Publisher: American Association for Cancer Research Country of Publication: United States NLM ID: 2984705R Publication Model: Print Cited Medium: Print ISSN: 0008-5472 (Print) Linking ISSN: 00085472 NLM ISO Abbreviation: Cancer Res Subsets: MEDLINE |
| أسماء مطبوعة: | Publication: Baltimore, Md. : American Association for Cancer Research Original Publication: Chicago [etc.] |
| مواضيع طبية MeSH: | Taxoids*, Cytochrome P-450 Enzyme System/*metabolism , Microsomes, Liver/*enzymology , Paclitaxel/*metabolism, Biotransformation/drug effects ; Humans ; Hydroxylation/drug effects ; Paclitaxel/analogs & derivatives ; Quercetin/pharmacology ; Troleandomycin/pharmacology |
| مستخلص: | The principal taxol biotransformation reaction of humans and of human hepatic in vitro preparations is 6 alpha-hydroxylation of the taxane ring, but a separate, minor hydroxylation pathway (metabolite B formation) also exists. Taxol metabolism was studied using membrane fractions from Hep G2 cells infected with recombinant vaccinia viruses that contain complementary DNAs encoding several human cytochrome P450 enzymes. Only P450 2C8 formed detectable 6 alpha-hydroxytaxol. Metabolite B formation was catalyzed by complementary DNA-expressed 3A3 and 3A4, but not by 3A5. Each P450 3A preparation catalyzed felodipine oxidation. The apparent Km and Vmax values for taxol 6 alpha-hydroxylation were 5.4 +/- 1.0 microM and 30 +/- 1.5 nmol/min/nmol P450, respectively, for complementary DNA-expressed P450 2C8; the values were 4.0 +/- 1.0 microM and 0.87 +/- 0.06 nmol/min/mg protein, respectively, for human hepatic microsomes. The inhibition of 6 alpha-hydroxytaxol formation by quercetin was competitive with an apparent Ki of 1.3 or 1.1 microM with 2C8 or hepatic microsomes, respectively; retinoic acid was inhibitory, showing an apparent Ki of 27 microM with hepatic microsomes; inhibition by tolbutamide was complex, weak, and unlikely to be clinically relevant. The correlation between hepatic 2C8 protein content and 6 alpha-hydroxytaxol formation was high (r2 = 0.82), while the correlation with 2C9 content was low (r2 = 0.38). These data show that human biotransformation routes of taxol result from catalysis by specific enzymes of two P450 families and that taxol 6 alpha-hydroxylation is a useful indicator of P450 2C8 activity in human hepatic microsomes. |
| المشرفين على المادة: | 0 (Taxoids) 153212-75-0 (6-hydroxytaxol) 9035-51-2 (Cytochrome P-450 Enzyme System) 9IKM0I5T1E (Quercetin) C4DZ64560D (Troleandomycin) P88XT4IS4D (Paclitaxel) |
| تواريخ الأحداث: | Date Created: 19941101 Date Completed: 19941123 Latest Revision: 20151119 |
| رمز التحديث: | 20231215 |
| PMID: | 7923194 |
| قاعدة البيانات: | MEDLINE |
| تدمد: | 0008-5472 |
|---|