PT  - JOURNAL ARTICLE
AU  - L von Meyerinck
AU  - B L Coffman
AU  - M D Green
AU  - R B Kirkpatrick
AU  - A Schmoldt
AU  - T R Tephly
TI  - Separation, purification, and characterization of digitoxigenin-monodigitoxoside UDP-glucuronosyltransferase activity.
DP  - 1985 Nov 01
TA  - Drug Metabolism and Disposition
PG  - 700--704
VI  - 13
IP  - 6
4099  - http://dmd.aspetjournals.org/content/13/6/700.short
4100  - http://dmd.aspetjournals.org/content/13/6/700.full
SO  - Drug Metab Dispos1985 Nov 01; 13
AB  - Glucuronidation of digitoxigenin-monodigitoxoside was investigated in liver microsomes from spironolactone-induced male Wistar rats. Isolation of a specific digitoxigenin-monodigitoxoside UDP-glucuronosyltransferase was possible utilizing chromatofocusing chromatography with a gradient from pH 10.1 to 8.0 after solubilizing the microsomal protein with the nonionic detergent Emulgen 911. The digitoxigenin-monodigitoxoside UDP-glucuronosyltransferase was further purified using UDP-hexanolamine Sepharose 4B affinity chromatography. The highly purified (75-fold) enzyme showed activity toward digitoxigenin-monodigitoxoside and slight activity toward digitoxigenin-bisdigitoxoside, whereas digitoxin and substrates for p-nitrophenol, 17 beta-OH steroid, and 3 alpha-OH steroid UDP-glucuronosyltransferases were not glucuronidated. In addition, bilirubin, morphine, estrone, 4-hydroxybiphenyl, and aromatic amines were not glucuronidated by this protein. These results strongly confirm the presence of a form of UDP-glucuronosyltransferase, which is highly specific for the glucuronidation of digitoxigenin-monodigitoxoside.