Journal of Lipid Research, Vol 30, 1281-1288, Copyright © 1989 by Lipid Research, Inc.
3-Diazirine-derivatives of bile salts for photoaffinity labeling
W Kramer and S Schneider
Institut fur Organische Chemie und Biochemie, Universitat Freiburg, Federal Republic of Germany.
New carbene-generating photolabile bile salt derivatives, 3,3-azo-7
alpha,12 alpha-dihydroxy-5 beta [7 beta-3H]cholan-24-oic acid and (3,3-
azo-7 alpha,12 alpha-dihydroxy-5 beta [7 beta-3H]cholan-24-oyl)-2-
aminoethanesulfonic acid were synthesized with high specific radioactivity.
These 3-diazirine-derivatives could be activated to the corresponding
carbenes by irradiation with ultraviolet light at 350 nm with a half-life
time of 2 min. The 3-diazirine derivatives behaved in enterohepatic
circulation like the natural bile salts. The uptake of [3H]taurocholate
into isolated hepatocytes was competitively inhibited by (3,3-azo-7
alpha,12 alpha-dihydroxy-5 beta-cholan-24-oyl)-2- aminoethanesulfonic acid
indicating that the 3,3-azo-derivative of taurocholate shares the hepatic
transport systems for natural bile salts. It was demonstrated that the
radioactively labeled 3-diazirine bile salt derivatives are useful probes
for photoaffinity labeling of bile salt binding proteins especially in
intact cells and tissues.