Abstract
The effect of Pb 2+ ions on the Na +,K +-ATPase was investigated in detail by means of steady-state fluorescence spectroscopy. Experiments were performed by using the electrochromic styryl dye RH421. It is shown that Pb 2+ ions can bind reversibly to the protein and do not affect the Na + and K + binding affinities in the E 1 and P-E 2 conformations of the enzyme. The pH titrations indicate that lead(II) favors binding of one H + to the P-E 2 conformation in the absence of K +. A model scheme is proposed that accounts for the experimental results obtained for backdoor phosphorylation of the enzyme in the presence of Pb 2+ ions. Taken together, our results clearly indicate that Pb 2+ bound to the enzyme stabilizes an E 2-type conformation. In particular, under conditions that promote enzyme phosphorylation, Pb 2+ ions are able to confine the Na +,K +-ATPase into a phosphorylated E 2 state.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
