The characteristics of 7a-deh~droxylase, a bile zvmes and intestinal bacterial transformation re-... more The characteristics of 7a-deh~droxylase, a bile zvmes and intestinal bacterial transformation re- acid-biotransforming enzyme, were determined using dia- lyzed cell extracts of Eubacterium sp. V.P.I. 12708. 7a-De- hydroxylase was induced by cholic acid in this organism. Induction by cholic acid resulted in the differential syn- thesis of at least five new polypeptides with molecular weights of 77,000, two at 56,000, 27,000 and 23,500, as de- termined by both one and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. The relative molecular weight of 7a-dehydroxylase activity was esti- mated by anaerobic Bio-Gel .4 1.5 M gel filtration chro- matography to be 114,000. NAD+ was the only cofactor found to consistently stimulate 7a-dehydroxylase activity in dialyzed cell extracts. The specific activity increased 4- to 6-fold with either cholic or chenodeoxycholic acid as a substrate in the presence of NAD+. NAD+ was also re- quired for the reduction of the A6-inter...
The characteristics of 7a-deh~droxylase, a bile zvmes and intestinal bacterial transformation re-... more The characteristics of 7a-deh~droxylase, a bile zvmes and intestinal bacterial transformation re- acid-biotransforming enzyme, were determined using dia- lyzed cell extracts of Eubacterium sp. V.P.I. 12708. 7a-De- hydroxylase was induced by cholic acid in this organism. Induction by cholic acid resulted in the differential syn- thesis of at least five new polypeptides with molecular weights of 77,000, two at 56,000, 27,000 and 23,500, as de- termined by both one and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. The relative molecular weight of 7a-dehydroxylase activity was esti- mated by anaerobic Bio-Gel .4 1.5 M gel filtration chro- matography to be 114,000. NAD+ was the only cofactor found to consistently stimulate 7a-dehydroxylase activity in dialyzed cell extracts. The specific activity increased 4- to 6-fold with either cholic or chenodeoxycholic acid as a substrate in the presence of NAD+. NAD+ was also re- quired for the reduction of the A6-inter...
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