Abstract
We have investigated the effect of Fe on the induction of ascorbate peroxidase (APX) in Fe-deficient Euglena cells that completely lacked APX activity. Addition of 0.13 mM Fe to Fe-deficient cells caused a two-phase induction of the APX activity: a sharp rapid increase in the first 3 h, followed by a steady gradual increase from 3 through 24 h. Cycloheximide had no effect on the initial increase of activity, but completely inhibited the subsequent increase. Immunoblot analyses using a monoclonal antibody (EAP1) raised against Euglena APX indicated that the former increase is due to activation of APX apo-protein and the latter one is due to de novo synthesis of the enzyme protein. However, Northern analysis revealed that the levels of APX transcripts remained constant, suggesting that the induction of Euglena APX by Fe is regulated at the post-transcriptional stage. The second increase of APX activity was also suppressed by the addition of succinyl acetone, an inhibitor of heme synthesis, suggesting that heme synthesis is essential for the synthesis of APX protein.
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.
