Definition of an epitope at the nucleotide binding site of the (Ca2+-Mg2+)-ATPase of sarcoplasmic reticulum by fluorescein labelling

1992 ◽  
Vol 20 (2) ◽  
pp. 123S-123S
Author(s):  
ANA M. MATA ◽  
RICHARD E.A. TUNWELL ◽  
ANTHONY G. LEE ◽  
J. MALCOLM EAST
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Site ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site ◽  
Definition Of

scholarly journals Definition of a Nucleotide Binding Site on Cytochromecby Photoaffinity Labeling

1996 ◽  
Vol 271 (31) ◽  
pp. 18379-18386 ◽  
Author(s):  
David B. McIntosh ◽  
Jonathan C. Parrish ◽  
Carmichael J. A. Wallace
Keyword(s):  
Binding Site ◽  
Photoaffinity Labeling ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site ◽  
Definition Of

scholarly journals Effects of Mg2+, anions and cations on the Ca2+ + Mg2+-activated ATPase of sarcoplasmic reticulum

1987 ◽  
Vol 245 (3) ◽  
pp. 723-730 ◽  
Author(s):  
H I Stefanova ◽  
R M Napier ◽  
J M East ◽  
A G Lee
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Kinetic Model ◽  
Atpase Activity ◽  
Binding Site ◽  
Conformational Transition ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site ◽  
Phosphorylated Form ◽  
Low Concentrations ◽  
Anions And Cations

In a previous paper [Gould, East, Froud, McWhirter, Stefanova & Lee (1986) Biochem. J. 237, 217-227] we presented a kinetic model for the activity of the Ca2+ + Mg2+-activated ATPase of sarcoplasmic reticulum. Here we extend the model to account for the effects on ATPase activity of Mg2+, cations and anions. We find that Mg2+ concentrations in the millimolar range inhibit ATPase activity, which we attribute to competition between Mg2+ and MgATP for binding to the nucleotide-binding site on the E1 and E2 conformations of the ATPase and on the phosphorylated forms of the ATPase. Competition is also suggested between Mg2+ and MgADP for binding to the phosphorylated form of the ATPase. ATPase activity is increased by low concentrations of K+, Na+ and NH4+, but inhibited by higher concentrations. It is proposed that these effects follow from an increase in the rate of dephosphorylation but a decrease in the rate of the conformational transition E1′PCa2-E2′PCa2 with increasing cation concentration. Li+ and choline+ decrease ATPase activity. Anions also decrease ATPase activity, the effects of I- and SCN- being more marked than that of Cl-. These effects are attributed to binding at the nucleotide-binding site, with a decrease in binding affinity and an increase in ‘off’ rate constant for the nucleotide.

Ca2+ versus Mg2+ Coordination at the Nucleotide-binding site of the Sarcoplasmic Reticulum Ca2+-ATPase

2007 ◽  
Vol 368 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Martin Picard ◽  
Anne-Marie Lund Jensen ◽  
Thomas L.-M. Sørensen ◽  
Philippe Champeil ◽  
Jesper Vuust Møller ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Binding Site ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site
Sign in / Sign up

Export Citation Format

Share Document