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: Solubilization and reconstitution of chick renal mitochondrial 25-hydroxyvitamin D3 24-hydroxylase.
    Author: Burgos-Trinidad M, Brown AJ, DeLuca HF.
    Journal: Biochemistry; 1986 May 06; 25(9):2692-6. PubMed ID: 3718974.
    Abstract:
    Chick kidney mitochondrial 25-hydroxyvitamin D3 24-hydroxylase has been solubilized with sodium cholate and reconstituted with NADPH, beef adrenal ferredoxin, and beef adrenal ferredoxin reductase, each component being essential for maximal 24-hydroxylase activity. The product 24(R),25-dihydroxyvitamin D3 was identified by cochromatography with synthetic compound on straight-phase and reversed-phase high-performance liquid chromatography and by periodate oxidation. The enzyme has an apparent Km for 25-hydroxyvitamin D3 of 0.67 microM. At 1 microM 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3 production is linear with time for up to 15 min and with protein concentrations of up to 2 mg/mL. The antioxidant diphenyl-p-phenylenediamine (1.3 X 10(-4) M) has no effect on this reaction. Reconstituted 24-hydroxylase activity is enhanced by the addition of NaCl and KCl up to 100 mM, with higher concentrations having an inhibitory effect. 1 alpha-Hydroxylase is not present in this preparation from vitamin D replete chicks. The similarities of this reconstituted system to the 25-hydroxyvitamin D3 1 alpha-hydroxylase and the adrenal systems suggest that the 25-hydroxyvitamin D3 24-hydroxylase is also a cytochrome P-450 type mixed-function oxidase.
    [Abstract] [Full Text] [Related] [New Search]