title: Lyophilized 7 alpha-hydroxysteroid dehydrogenase: a stable enzyme preparation for routine bile acid analysis.
abstract: 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.
mesh_terms: D001647:Bile Acids and Salts / Q000032:analysis*; D002635:Chenodeoxycholic Acid; D004355:Drug Stability; D004386:Duodenum / Q000032:analysis; D004926:Escherichia coli / Q000201:enzymology; D005612:Freeze Drying; D006801:Humans; D006913:Hydroxysteroid Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008722:Methods; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D001647:Bile Acids and Salts; D002635:Chenodeoxycholic Acid; D012964:Sodium; D006913:Hydroxysteroid Dehydrogenases; D011188:Potassium