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: Characterization of mitochondrial cytochromes P-450 from pig kidney and liver catalysing 26-hydroxylation of 25-hydroxyvitamin D3 and C27 steroids.
    Author: Bergman T, Postlind H.
    Journal: Biochem J; 1991 Jun 01; 276 ( Pt 2)(Pt 2):427-32. PubMed ID: 2049072.
    Abstract:
    The properties of cytochrome P-450 from pig kidney mitochondria, catalysing 26-hydroxylation of 25-hydroxyvitamin D3 and C27 steroids [Postlind & Wikvall (1989) Biochem. Biophys. Res. Commun. 159, 1135-1140; Postlind (1990) Biochem. Biophys. Res. Commun. 168, 261-266], were compared with those of a 26-hydroxylating cytochrome P-450 from pig liver mitochondria. The liver enzyme was purified to a cytochrome P-450 content of 7.4 nmol/mg of protein and showed only one protein band with an apparent Mr of 53,000 upon SDS/PAGE. The cytochrome P-450 catalysed 26-hydroxylation of 25-hydroxyvitamin D3, cholesterol and 5 beta-cholestane-3 alpha, 7 alpha-diol at rates of 361, 1090 and 2065 pmol/min per nmol of cytochrome P-450. A monoclonal antibody against the purified liver mitochondrial cytochrome P-450 26-hydroxylase (cytochrome P-450(26] was prepared. After coupling to Sepharose, the antibody was able to bind to cytochrome P-450(26) from liver as well as from kidney mitochondria and to immunoprecipitate the 26-hydroxylase activity towards 25-hydroxyvitamin D3 and cholesterol when assayed in a reconstituted system. After SDS/PAGE and immunoblotting with the antibody, the cytochrome P-450(26) was detected in the purified liver and kidney preparations. These results indicate that similar species of cytochrome P-450 catalyse 26-hydroxylation of 25-hydroxyvitamin D3 and C27 steroids in liver and kidney mitochondria. The results with the monoclonal antibody together with the finding that cholesterol competitively inhibits the 26-hydroxylation of 25-hydroxyvitamin D3 further indicate that 26-hydroxylation of 25-hydroxyvitamin D3 and cholesterol is catalysed by the same species of cytochrome P-450 in each tissue. The N-terminal amino acid sequence of cytochrome P-450(26) in kidney mitochondria resembled that of pig kidney microsomal 25-hydroxylase active in 25-hydroxylation of vitamin D3 and C27 steroids, whereas the sequence of pig liver mitochondrial cytochrome P-450(26) differed from those of rabbit and rat liver mitochondrial 26-hydroxylases as well as from those of other hitherto isolated mammalian cytochromes P-450.
    [Abstract] [Full Text] [Related] [New Search]