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: Properties of a Zn(2+)-glycerophosphocholine cholinephosphodiesterase from bovine brain membranes.
    Author: Sok DE.
    Journal: Neurochem Res; 1996 Oct; 21(10):1193-9. PubMed ID: 8923480.
    Abstract:
    A Zn(2+)-glycerophosphocholine cholinephosphodiesterase was purified with a specific activity of 4.6 mumole/min.mg protein from bovine brain membranes by procedures involving PI-PLC solubilization, concanavalin A affinity chromatography, CM-sephadex chromatography and Sephadex G-150 chromatography. Based on molecular weight determination gel chromatography and SDS polyacrylamide gel electrophoresis, the phosphodiesterase activity appears to be a dimeric protein (110 kDa) composed of two subunits with a molecular weight of approximately 54 kDa. The K(m) value for p-nitrophenylphosphocholine and the optimum pH were found to be 16 microM and pH 10.5, respectively. The phosphodiesterase was inhibited by Cu2+, but not the other divalent metal ions. The activity of the apoenzyme was remarkably activated by Co2+ or Zn2+, but not Mn2+ or Mg2+. In addition, the inactivation of the enzyme in glycine buffer was prevented by Mn2+ or Zn2+, but not Co2+ or Mg2. In a separate experiment, comparing properties of the purified and membrane-bound phosphodiesterases, the forms of two enzymes were quite similar except in stability. Both enzymes were more stable at pH 7.4 than pH 5 or 10. However, the membrane-bound enzyme was more stable than the soluble enzyme at all three pHs. These data suggest that the activity of the phosphodiesterase may be stabilized in-vivo.
    [Abstract] [Full Text] [Related] [New Search]