Abstract
The metabolism of cysteine and cysteinesulphinate was studied in freshly isolated rat hepatocytes. Over 80% of the 14CO2 formed from [1-14C]cysteinesulphinate could be accounted for by production of hypotaurine plus taurine in incubations of rat hepatocytes with either 1 mM- or 25 mM-cysteinesulphinate. In similar incubations with 1 mM- or 25 mM-cysteine, less than 10% of 14CO2 evolution from [1-14C]cysteine could be accounted for by production of hypotaurine plus taurine. In incubations with cysteine, but not with cysteinesulphinate, the production of urea and ammonia was substantially increased above that observed in incubations without substrate. Addition of unlabelled cysteinesulphinate did not affect 14CO2 production from [1-14C]cysteine. Addition of 2-oxoglutarate resulted in a marked increase in cysteinesulphinate catabolism via the transamination pathway, but addition of neither 2-oxoglutarate nor pyruvate to the incubation system had any effect on cysteine catabolism. Inhibition of cystathionase with propargylglycine decreased 14CO2 production from [1-14C]cysteine about 50% and markedly decreased production of ammonia plus urea N; cysteinesulphinate catabolism by cysteinesulphinate-independent pathways in the rat hepatocyte and, furthermore, that cleavage of cyst(e)ine by cystathionase may be an important physiological pathway for cysteine catabolism in rat liver.
Sign-in/Register to access full text options 
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.
