PMID: 7023940Jul 1, 1981Paper

Dependence on pH of parameters of lactose transport in Escherichia coli. Evidence for an essential protonated group of the carrier

European Journal of Biochemistry
M Bentaboulet, A Kepes

Abstract

The kinetic parameters Km and V of transported by the lactose permease of Escherichia coli have been explored in the pH range 4.8--9.2. Besides uphill transport of methylthiogalactoside, two other criteria have been used. Downhill transport of o-nitrophenylgalactoside and substrate protection of the carrier against thiol reagents have both been explored in normal aerated cells and in cells inhibited by cyanide plus azide, therefore unable to build up a proton-motive force. V of the transport processes did not exhibit a major pH dependence that would support an essential protonation. Ktransport for methylthiogalactoside and for o-nitrophenylgalactoside in the energized and in the inhibited state did not show a sharp pH dependence between pH 4.8 and 8.0, but increased between pH 8 and 9, as would be expected if there were an essential protonated group with a pK of 8--8.4, depending on the test utilized. Substrate protection allowed the calculation of a Kprotection which was close to the corresponding Ktransport and was also largely independent of pH between 5 and 8 and independent of energy supply. The role of energization in substrate-carrier binding and the role of the essential protonation in the context of the proton symptom ...Continue Reading

References

Mar 1, 1976·Journal of Bacteriology·J L Flagg, T H Wilson
Apr 1, 1976·European Journal of Biochemistry·E PadanH Rottenberg
Nov 15, 1977·Biochimica Et Biophysica Acta·M Bentaboulet, A Kepes
Aug 7, 1972·Biochemical and Biophysical Research Communications·H U Schairer, B A Haddock
Jun 1, 1973·Proceedings of the National Academy of Sciences of the United States of America·H HirataF M Harold
Mar 1, 1973·The Biochemical Journal·I C West, P Mitchell
Oct 1, 1973·Proceedings of the National Academy of Sciences of the United States of America·J P ReevesH R Kaback
Nov 9, 1970·Biochemical and Biophysical Research Communications·I C West
Sep 1, 1965·Proceedings of the National Academy of Sciences of the United States of America·C F Fox, E P Kennedy
May 1, 1967·The Journal of General Physiology·P F CurranR E Fuisz
Jul 22, 1980·Biochemistry·H FelleH R Kaback
Aug 1, 1961·The Biochemical Journal·G N WILKINSON
May 6, 1960·Biochimica Et Biophysica Acta·A KEPES

❮ Previous
Next ❯

Citations

Jan 1, 1985·Annals of the New York Academy of Sciences·J P Deshusses
May 1, 1983·Journal of Bacteriology·T Hackstadt, J C Williams
Mar 13, 1986·Biochimica Et Biophysica Acta·J K Wright

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.