Durch Säure-Base-Übergang induzierte ATP-Pa-Austauschreaktion in Chloroplasten

1967 ◽  
Vol 22 (10) ◽  
pp. 1051-1054 ◽  
Author(s):  
Reinhard Bachofen ◽  
Ingrid Specht-Jürgensen
Keyword(s):  
Exchange Reaction ◽  
Atp Synthesis ◽  
Reducing Agent ◽  
Acid Base ◽  
Base Transition ◽  
Exchange Activity

Chloroplasts possess an ATP-Pa-exchange activity, which is induced by a transition from acid to base. The reaction is dependant on the presence of Mg2⨁ and a reducing agent, DTT. The exchange reaction induced by acid-base transition has properties similar to the light-triggered ATP–Pa-exchange and the ATP-synthesis induced by acid-base transition.

scholarly journals Competition between excited state proton and OH− transport via a short water wire: solvent effects open the gate

2014 ◽  
Vol 16 (26) ◽  
pp. 13047-13051 ◽  
Author(s):  
Gül Bekçioğlu ◽  
Christoph Allolio ◽  
Maria Ekimova ◽  
Erik T. J. Nibbering ◽  
Daniel Sebastiani
Keyword(s):  
Excited State ◽  
Exchange Reaction ◽  
Quantum Chemical Calculations ◽  
Solvent Effects ◽  
Quantum Chemical ◽  
Proton Exchange ◽  
Acid Base

We investigate the acid–base proton exchange reaction in a microsolvated bifunctional chromophore by means of quantum chemical calculations.

Basolateral ammonium transport by the mouse inner medullary collecting duct cell (mIMCD-3)

2004 ◽  
Vol 287 (4) ◽  
pp. F628-F638 ◽  
Author(s):  
Mary E. Handlogten ◽  
Seong-Pyo Hong ◽  
Connie M. Westhoff ◽  
I. David Weiner
Keyword(s):  
Collecting Duct ◽  
Duct Cell ◽  
Ammonium Transport ◽  
Transport Activity ◽  
Acid Base ◽  
Ammonia Transport ◽  
Medullary Collecting Duct ◽  
Extracellular Sodium ◽  
Permeable Support ◽  
Exchange Activity

The renal collecting duct is the primary site for the ammonia secretion necessary for acid-base homeostasis. Recent studies have identified the presence of putative ammonia transporters in the collecting duct, but whether the collecting duct has transporter-mediated ammonia transport is unknown. The purpose of this study was to examine basolateral ammonia transport in the mouse collecting duct cell (mIMCD-3). To examine mIMCD-3 basolateral ammonia transport, we used cells grown to confluence on permeable support membranes and quantified basolateral uptake of the radiolabeled ammonia analog [14C]methylammonia ([14C]MA). mIMCD-3 cell basolateral MA transport exhibited both diffusive and transporter-mediated components. Transporter-mediated uptake exhibited a Kmfor MA of 4.6 ± 0.2 mM, exceeded diffusive uptake at MA concentrations below 7.0 ± 1.8 mM, and was competitively inhibited by ammonia with a Kiof 2.1 ± 0.6 mM. Transporter-mediated uptake was not altered by inhibitors of Na+-K+-ATPase, Na+-K+-2Cl−cotransporter, K+channels or KCC proteins, by excess potassium, by extracellular sodium or potassium removal or by varying membrane potential, suggesting the presence of a novel, electroneutral ammonia-MA transport mechanism. Increasing the outwardly directed transmembrane H+gradient increased transport activity by increasing Vmax. Finally, mIMCD-3 cells express mRNA and protein for the putative ammonia transporter Rh B-glycoprotein (RhBG), and they exhibit basolateral RhBG immunoreactivity. We conclude that mIMCD-3 cells express a basolateral electroneutral NH4+/H+exchange activity that may be mediated by RhBG.

Phosphate exchange and ATP synthesis by DMSO-pretreated purified bovine mitochondrial ATP synthase

2001 ◽  
Vol 353 (2) ◽  
pp. 215-222
Author(s):  
Seelochan BEHARRY ◽  
Philip D. BRAGG
Keyword(s):  
Exchange Reaction ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Catalytic Site ◽  
Phosphate Removal ◽  
Subsequent Removal ◽  
F1fo Atp Synthase ◽  
Mitochondrial Atp Synthase ◽  
Phosphate Exchange

Purified soluble bovine mitochondrial F1Fo-ATP synthase contained 2mol of ATP, 2mol of ADP and 6mol of Pi/mol. Incubation of this enzyme with 1mM [32P]Pi caused the exchange of 2mol of Pi/mol of F1Fo-ATP synthase. The labelled phosphates were not displaced by ATP. Transfer of F1Fo-ATP synthase to a buffer containing 30% (v/v) DMSO and 1mM [32P]Pi resulted in the loss of bound nucleotides with the retention of 1mol of ATP/mol of F1Fo-ATP synthase. Six molecules of [32P]Pi were incorporated by exchange with the existing bound phosphate. Removal of the DMSO by passage of the enzyme through a centrifuged column of Sephadex G-50 resulted in the exchange of one molecule of bound [32P]Pi into the bound ATP. Azide did not prevent this [32P]Pi ↔ ATP exchange reaction. The bound labelled ATP could be displaced from the enzyme by exogenous ATP. Addition of ADP to the DMSO-pretreated F1Fo-ATP synthase in the original DMSO-free buffer resulted in the formation of an additional molecule of bound ATP. It was concluded that following pretreatment with and subsequent removal of DMSO the F1Fo-ATP synthase contained one molecule of ATP at a catalytic site which was competent to carry out a phosphateŐATP exchange reaction using enzyme-bound inorganic radiolabelled phosphate. In the presence of ADP an additional molecule of labelled ATP was formed from enzyme-bound Pi at a second catalytic site. The bound phosphateŐATP exchange reaction is not readily accommodated by current mechanisms for the ATP synthase.

Energization of NTP-NDP Kinase by Acid-base Transition Leading to ATP Formation

1974 ◽  
Vol 76 (1) ◽  
pp. 233-235 ◽  
Author(s):  
Tatsuo OKU ◽  
Kazuo HOSOI ◽  
Gilbu SOE ◽  
Tomisaburo KAKUNO ◽  
Takekazu HORIO
Keyword(s):  
Ndp Kinase ◽  
Acid Base ◽  
Atp Formation ◽  
Base Transition

Doping of polyaniline by thermal acid–base exchange reaction

2004 ◽  
Vol 24 (1-2) ◽  
pp. 39-41 ◽  
Author(s):  
Yongku Kang ◽  
Sang Kyung Kim ◽  
Changjin Lee
Keyword(s):  
Exchange Reaction ◽  
Acid Base ◽  
Base Exchange
Sign in / Sign up

Export Citation Format

Share Document