Journal of Lipid Research, Vol 16, 244-246, Copyright © 1975 by Lipid Research, Inc.
Lyophilized 7 alpha-hydroxysteroid dehydrogenase: a stable enzyme preparation for routine bile acid analysis
IA Macdonald, CN Williams and DE Mahony
Preparations of 7 alpha-hydroxysteroid dehydrogenase (7 alpha-HSDH) from
Escherichia coli strain 23 can be frozen and thawed without significant
loss of activity. 7 alpha-HSDH may then be lyophilized into powder form,
which is stable for more than 6 months (3% loss of activity). The
lyophilized 7 alpha-HSDH preparation has the additional advantage over
previously described preparations of a low and stable fluorescence
background when applied to the fluorometric estimation of bile acids,
especially in combination with thin-layer chromatography. Analysis of
duodenal aspirates from 18 normal subjects gave bile acid ratios identical
with those reported earlier and obtained by using gas- liquid
chromatography. A significant difference in the glycine: taurine ratio
between males and females was observed.