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: Pyridoxal 5'-phosphate probes at Lys-480 can sense the binding of ATP and the formation of phosphoenzymes in Na+,K(+)-ATPase.
    Author: Kaya S, Tsuda T, Hagiwara K, Fukui T, Taniguchi K.
    Journal: J Biol Chem; 1994 Mar 11; 269(10):7419-22. PubMed ID: 8125960.
    Abstract:
    The Lys-480 in the alpha-subunits of Na+,K(+)-ATPase from pig kidneys was specifically modified with pyridoxal 5'-phosphate (PLP) or pyridoxal 5'-diphospho-5'-adenosine (AP2PL) probes in the presence of NaCl. The site was shown to be the same as the ATP-protectable binding of these probes (Hinz, H.R., and Kirley, T.L. (1990) J. Biol. Chem. 265, 10260-10265). Modifications strongly reduced both Na+,K(+)-ATPase activity and the amount of Na(+)-dependent phosphoenzyme from [32P]ATP but not from [32P]acetyl-phosphate (AcP). Addition of AcP to the enzyme induced a slight decrease in the fluorescence of the PLP probe in the presence of 2 M NaCl and 4 mM MgCl2 but a single exponential increase in the presence of 16 mM NaCl and 4 mM MgCl2. The addition of ATP induced single exponential fluorescence increases at both Na+ concentrations. The data show that these probes can sense molecular events related to the formation of phosphoenzymes induced by AcP and presumably to the formation of Mg-Na-ATP-enzyme complex. The data also suggest that PLP or AP2PL probes at Lys-480 in the presence of Na+ and Mg2+ do not affect the transphosphorylation from AcP to Asp-369 to form phosphoenzymes but that they inhibit the transphosphorylation from the gamma-phosphoryl group of ATP and also ATP binding in the absence of Mg2+.
    [Abstract] [Full Text] [Related] [New Search]