Journal of Lipid Research, Vol 27, 905-909, Copyright © 1986 by Lipid Research, Inc.
Reaffirmation of the validity of enzymatic cleavage of lithocholic acid from N-epsilon-lithocholyl-L-lysine and N-alpha-CBZ-N-epsilon- lithocholyl-L-lysine
PP Nair, G Kessie and VP Flanagan
N-epsilon-lithocholyl-L-lysine or N-alpha-CBZ-N-epsilon-lithocholyl-L-
lysine when incubated overnight at 37 degrees C with 3 K units of
clostridial cholanoylaminoacid hydrolase (from Clostridium perfringens ATCC
19574) in the presence of disodium EDTA (0.1 M), beta- mercaptoethanol (0.1
M), and sodium acetate buffer, pH 5.6, released free lithocholic acid. The
latter material was isolated by thin-layer chromatography and identified by
combined gas-liquid chromatography- mass spectrometry in the full scan and
selected-ion mode. In order to maintain its activity, the enzyme was always
stored in 1.0-ml aliquots at temperatures below -20 degrees C and each
aliquot when thawed was used immediately; any left over enzyme was never
reused. Contrary to the observations of Yanagisawa et al. (J. Lipid Res.
1984. 25: 1263- 1271) the results of this study reaffirm the validity of
the original observations on the enzymatic cleavage of lithocholic acid
from tissue- bound form.