+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Cooperative proton and calcium binding by sarcoplasmic reticulum ATPase

Cooperative proton and calcium binding by sarcoplasmic reticulum ATPase

Febs Letters 308(1): 59-61

The classic work on binding of calcium to CaATPase is analyzed by an objective non-linear least squares procedure of 74 data points over six pH values. Binding of two calciums to the basic form of the sites occurs with an equilibrium stability constant product of log K1K2 = 13.2. Owing to competition from protons, this value drops in acidic and neutral solutions, becoming, for example, 11.9 at pH 6.8. Binding of the two calciums is so strongly cooperative that its extent is difficult to estimate reliably; there is very little of the one calcium species. Two protons are also bound cooperatively to the calcium sites. In solutions of calcium free protein, at pH less than 7.6 the predominant species holds two protons at the calcium sites, while at greater pH the dominant species bears no protons; there is very little of the intermediate one proton species. The analysis also reveals the likely presence of a small, less than statistical, amount of a ternary complex bearing one calcium and one proton.

(PDF emailed within 0-6 h: $19.90)

Accession: 039686959

Download citation: RISBibTeXText

PMID: 1322841

DOI: 10.1016/0014-5793(92)81050-v

Related references

Proton nmr studies on nucleotide binding to the sarcoplasmic reticulum calcium atpase ec determination of the conformations of bound nucleotides by the measurement of proton proton transferred nuclear overhauser enhancements. European Journal of Biochemistry 128(1): 113-118, 1982

Cooperative calcium binding and ATPase activation in sarcoplasmic reticulum vesicles. Journal of Biological Chemistry 255(7): 3025-3031, 1980

Equilibrium cooperative binding of calcium and protons by sarcoplasmic reticulum ATPase. Proceedings of the National Academy of Sciences of the United States of America 79(13): 3978-3982, 1982

Two types of proton-modulated calcium binding in the sarcoplasmic reticulum Ca(2+)-ATPase. I. A model of two different conformations of chemically equivalent ATPase molecules. Journal of Biological Chemistry 269(49): 30818-30821, 1994

Two types of proton-modulated calcium binding in the sarcoplasmic reticulum Ca(2+)-ATPase. II. Characteristics of their calcium bindings. Journal of Biological Chemistry 269(49): 30822-7, 1994

Chemical modification of the calcium ion dependent atpase ec of sarcoplasmic reticulum from skeletal muscle part 1 binding of n ethyl maleimide to sarcoplasmic reticulum evidence for sulfhydryl groups in the active site of atpase and for conformational changes induced by adp and atp. Journal of Biochemistry 79(3): 649-654, 1976

Calcium binding to sarcoplasmic reticulum ATPase revisited Influence of proton and magnesium on its cooperativity. Biophysical Journal 64(2 PART 2): A333, 1993

Cooperative effects of calcium and strontium on sarcoplasmic reticulum atpase. Archives of Biochemistry & Biophysics 251(1): 9-16, 1986

Calcium and proton dependence of sarcoplasmic reticulum ATPase. Biophysical Journal 44(2): 271-280, 1983

Reaction mechanism of the calcium ion dependent atpase ec of sarcoplasmic reticulum from skeletal muscle part 6 cooperative transition of atpase activity during the initial phase. Journal of Biochemistry (Tokyo) 70(2): 279-291, 1971

The reconstituted calcium atpase from sarcoplasmic reticulum mediates calcium proton exchange. Biophysical Journal 45(2 PART 2): 189A, 1984

Monoclonal antibodies to the calcium magnesium dependent atpase of skeletal muscle sarcoplasmic reticulum cross reactivity with atpase isozymes and other calcium binding proteins. Bronner, F And M Peterlik (Ed ) Progress in Clinical And Biological Research, Vol 168 Epithelial Calcium And Phosphate Transport: Molecular And Cellular Aspects; Proceedings Of The 2nd International Workshop on Calcium And Phosphate Across Biomembranes, Vienna, Austria, Mar 5-7, Xxiii+392p Alan R Liss, Inc : New York N Y , Usa Illus 19-24, 1984

The oligomeric structure of the proton atpase from neurospora crassa plasma membranes evidence from radiation inactivation and comparison with the calcium atpase of sarcoplasmic reticulum. Federation Proceedings 44(3): 612, 1985

Neodymium and cobalt binding to sarcoplasmic reticulum calcium atpase an estimation of the distance from the atp binding site to the high affinity calcium binding sites. Journal of Biological Chemistry 259(23): 14651-14656, 1984

Influence of the 53kda glycoprotein on cooperative behavior of the sarcoplasmic reticulum calcium atpase. Biophysical Journal 55(2 PART 2): 481A, 1989