Abstract
3 alpha-Hydroxysteroid dehydrogenase was used to monitor bile acid production by rat hepatocyte suspensions. Several observations suggested that the method lacked specificity and detected some other metabolites besides bile acids. This was due to a malate dehydrogenase activity present in four different commercial enzyme preparations of 3 alpha-hydroxysteroid dehydrogenase. It is concluded that considerable error can be caused by this contaminating malate dehydrogenase activity, especially in the case of low bile acid concentration in the sample.
Highlights
In an attempt to study bile acid synthesis and its stimulation by malate [4], isolated hepatocytes were incubated with 1.25-5 mM L-malate
The amount of NADH, generated in the hydroxysteroid dehydrogenase (HSD) assay at 60 min incubation time was higher than at 120 min (Fig. 1);when expressed in bile salt concentration, this would indicate a disappearance of bile acids during the incubation
As there seemed to be roughly a stoichiometry between the NADHz signal and the L-malate added at the onset of incubation, we wondered whether Lmalate caused the NADH2 formation
Summary
Taurocholate was from Roth (Karlsruhe,Germany) and was used as standard for the HSD assay after two-Abreviations: HSD, 3a-hydroxysteroid dehydrogenase (E.C.1.1.1.50); MDH, malate dehydrogenase, L-malate: NAD+ oxidoreductase (E.C.1.1.1.37).fold recrystallization from ethanol-diethyl ether.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
