Abstract
Addition of hemin (5–200 μM) to a rabbit reticulocyte iron-free incubation medium, resulted in a progressive inhibition of heme synthesis as measured by incorporation of ( 14C)-glycine. In contrast when ( 14C) δ-aminolevulinic acid incorporation into heme was studied, significant inhibition below that of the ( 14C)-glycine control only occurred with hemin concentrations greater than 100 μM. Hemin progressively inhibited cellular and mitochondrial δ-aminolevulinic acid synthetase activity, as well as cellular δ-aminolevulinic acid dehydratase activity. The results indicated that elevated levels of hemin initially control heme synthesis by feedback inhibition at the rate-limiting enzyme of heme synthesis, δ-aminolevulinic acid synthetase. Hemin inhibition of δ-aminolevulinic acid dehydratase is only significant for the entrire heme synthetic pathway when greater than one-third of this enzyme's activity is inhibited.
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 callMore From: Biochemical and Biophysical Research Communications
Disclaimer: 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.
