HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by White, B. A. Articles by Hylemon, P. B. Search for Related Content PubMed PubMed Citation Articles by White, B. A. Articles by Hylemon, P. B. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol 23, 145-153, Copyright © 1982 by Lipid Research, Inc.

ARTICLES

7 beta-Dehydroxylation of ursodeoxycholic acid by whole cells and cell extracts of the intestinal anaerobic bacterium, Eubacterium species V.P.I. 12708

BA White, RJ Fricke and PB Hylemon

Whole cells and cell extracts of Eubacterium species V. P. I. 12708 7- dehydroxylated [3H]ursodeoxycholic acid or [14C]chenodeoxycholic forming lithocholic acid. 7 beta-Dehydroxylation specific activity was 146 and 386 nmol hr-1 mg protein-1 for cell extracts and whole cells, respectively. 7 alpha- or 7 beta-Dehydroxylation activity was detected only in whole cells or cell extracts prepared from cultures grown in the presence of cholic acid. The addition of NAD+ (0.5 mM) to anaerobically dialyzed cell extracts stimulated 7 beta- and 7 alpha- dehydroxylation activity by 5- and 40-fold, respectively. The level of 7 beta-dehydroxylation specific activity was approximately 3- to 5-fold lower than 7 alpha-dehydroxylation in whole cells and 3-fold lower in cell extracts. Substrate saturation kinetics for ursodeoxycholic acid and chenodeoxycholic acid were hyperbolic and showed substrate inhibition at concentrations above 200 microM. The apparent Km values for ursodeoxycholic and chenodeoxycholic acid were 14.5 microM and 49 microM, respectively. Both 7 alpha- and 7 beta-dehydroxylase activities were inactivated (60% to 70%) by heating for 6 min at 45 degrees C. Moreover, both activities co-eluted from a anaerobic Bio-Gel A 1.5-M column as a single peak at approximately 114,000 (Mr). These data show that this intestinal anaerobic bacterium has both 7 alpha- and 7 beta- dehydroxylase activities which may be catalyzed by the same enzyme.U
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. M. Ridlon, D.-J. Kang, and P. B. Hylemon Bile salt biotransformations by human intestinal bacteria J. Lipid Res., February 1, 2006; 47(2): 241 - 259. [Abstract] [Full Text] [PDF]

				R. K. Wali, D. Stoiber, L. Nguyen, J. Hart, M. D. Sitrin, T. Brasitus, and M. Bissonnette Ursodeoxycholic Acid Inhibits the Initiation and Postinitiation Phases of Azoxymethane-induced Colonic Tumor Development Cancer Epidemiol. Biomarkers Prev., November 1, 2002; 11(11): 1316 - 1321. [Abstract] [Full Text] [PDF]

				H. J. Eyssen, G. De Pauw, and J. Van Eldere Formation of Hyodeoxycholic Acid from Muricholic Acid and Hyocholic Acid by an Unidentified Gram-Positive Rod Termed HDCA-1 Isolated from Rat Intestinal Microflora Appl. Envir. Microbiol., July 1, 1999; 65(7): 3158 - 3163. [Abstract] [Full Text]

				G. S. TINT, G. SALEN, A. COLALILLO, D. GRABER, D. VERGA, J. SPECK, and S. SHEFER Ursodeoxycholic Acid: A Safe and Effective Agent for Dissolving Cholesterol Gallstones Ann Intern Med, September 1, 1982; 97(3): 351 - 356. [Abstract] [PDF]