Catalysis by isolated beta-subunits of the ATP Synthase/ATPase from Thermophilic bacillus PS3. Hydrolysis of pyrophosphate.

Journal of Bioenergetics and Biomembranes
Concepción José-NuñezMarietta Tuena de Gómez-Puyou

Abstract

Although the capacity of isolated beta-subunits of the ATP synthase/ATPase to perform catalysis has been extensively studied, the results have not conclusively shown that the subunits are catalytically active. Since soluble F(1) of mitochondrial H(+)-ATPase can bind inorganic pyrophosphate (PP(i)) and synthesize PP(i) from medium phosphate, we examined if purified His-tagged beta-subunits from Thermophilic bacillus PS3 can hydrolyze PP(i). The difference spectra in the near UV CD of beta-subunits with and without PP(i) show that PP(i) binds to the subunits. Other studies show that beta-subunits hydrolyze [(32)P] PP(i) through a Mg(2+)-dependent process with an optimal pH of 8.3. Free Mg(2+) is required for maximal hydrolytic rates. The Km for PP(i) is 75 microM and the Vmax is 800 pmol/min/mg. ATP is a weak inhibitor of the reaction, it diminishes the Vmax and increases the Km for PP(i). Thus, isolated beta-subunits are catalytically competent with PP(i) as substrate; apparently, the assembly of beta-subunits into the ATPase complex changes substrate specificity, and leads to an increase in catalytic rates.

References

Sep 1, 1989·Proceedings of the National Academy of Sciences of the United States of America·K Miwa, M Yoshida
Apr 1, 1985·Proceedings of the National Academy of Sciences of the United States of America·D Khananshvili, Z Gromet-Elhanan
Jan 10, 1995·Archives of Biochemistry and Biophysics·A Sosa, H Celis
Mar 9, 1993·Biochemistry·M Tuena de Gómez-PuyouA Gómez-Puyou
Nov 1, 1995·Biochemical Society Transactions·A E SeniorM K al-Shawi
Dec 15, 1996·Structure·P HeikinheimoA Goldman
Sep 3, 1999·FEBS Letters·M BaltscheffskyH Baltscheffsky
Nov 27, 1999·Science·D StockJ E Walker
Dec 3, 1999·Biochemical and Biophysical Research Communications·H N PeñaG Pérez-Hernández
Feb 1, 1993·Origins of Life and Evolution of the Biosphere : the Journal of the International Society for the Study of the Origin of Life·A Brack
Jul 19, 2002·Proteomics·Juliette BardelJacques Bourguignon
Dec 5, 2002·Archives of Biochemistry and Biophysics·Gerardo Pérez-HernándezMarietta Tuena de Gómez-Puyou
Dec 17, 2004·Journal of the American Chemical Society·Hiromasa YagiHideo Akutsu
Aug 27, 2005·Mitochondrion·Marco ZancaniAngelo Vianello

❮ Previous
Next ❯

Citations

Apr 2, 2011·The Journal of Physical Chemistry. a·Ulrich KleinekathöferKlaus Schulten

❮ Previous
Next ❯

Related Concepts

Related Feeds

ATP Synthases

ATP synthases are enzymes located in the inner mitochondrial membrane that catalyze the synthesis of ATP during cellular respiration. Discover the latest research on ATP synthases here.

Bacterial Respiration

This feed focuses on cellular respiration in bacteria, known as bacterial respiration. Discover the latest research here.