These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Kinetic characterization of the reconstituted ornithine carrier from rat liver mitochondria.
    Author: Indiveri C, Palmieri L, Palmieri F.
    Journal: Biochim Biophys Acta; 1994 Dec 30; 1188(3):293-301. PubMed ID: 7803446.
    Abstract:
    The ornithine carrier was purified from rat liver mitochondria and reconstituted into liposomes by removing the detergent from mixed micelles by hydrophobic chromatography on Amberlite XAD-2. The efficiency of reconstitution was optimized with respect to the concentration of protein and phospholipid, the Triton X-100/phospholipid ratio, the Amberlite/detergent ratio and the number of passages through a single Amberlite column. The activity of the carrier was influenced by the phospholipid composition of the liposomes, increasing in the presence of acidic phospholipids and decreasing in the presence of dioleoylphosphatidylcholine. In the reconstituted system the incorporated ornithine carrier catalyzed a first-order reaction of ornithine/ornithine or ornithine/citrulline exchange. The maximum transport rate of external [14C]ornithine was 3.2 mmol/min per g protein at 25 degrees C. This value was independent of the type of substrate present at the external or internal space of the liposomes (ornithine, citrulline and lysine). The half-saturation constant (Km) was 0.16 mM for ornithine, 1.2 mM for lysine and 3.6 mM for citrulline. The activation energy of the ornithine/ornithine exchange reaction was 89 kJ/mol. The rate of exchange had a pH optimum at 8 and was inhibited by cations.
    [Abstract] [Full Text] [Related] [New Search]