+ Site Statistics
+ Resolve Accession
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
Submit PDF Full TextSubmit PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Differences in uncoupling effects associated with the uptake of lactose and dansyl galactoside in escherichia coli membrane active transport vs. specific binding

, : Differences in uncoupling effects associated with the uptake of lactose and dansyl galactoside in escherichia coli membrane active transport vs. specific binding. Archives of Biochemistry and Biophysics 202(1): 126-136

Cytoplasmic membrane vesicles isolated from E. coli take up dansyl-galactoside, a fluorescent competitive inhibitor of lactose transport, to much lower levels than lactose. An initial interpretation, based on the study of the fluorescent changes accompanying the energy-dependent uptake, was that it represented a one-to-one specific binding to the lac carrier protein which was not followed by transport. Recently, on the basis of a new estimation of the number of lac carrier in the membrane, it was advanced that the uptake of dansyl-galactoside represents a nonspecific binding on the inner surface of the membrane following transport. One discriminates between the 2 interpretations by comparing the effects of lactose and dansyl-galactoside uptake on the electrochemical gradient of protons (, generated by the oxidation of substrates, and on the uptake of proline. Indeed, it is known that the rate of lactose transport is such that it leads, as a consequence of the lactose/H+ symport, to an observable decrease of, and secondary to this decrease to an inhibition of the uptake of proline transported at much lower rate. The rates of uptake of lactose and dansyl-galactoside by the membrane vesicles are similar; yet the uptake of dansyl-galactoside does not lead to the uncoupling effects which are associated with the uptake of lactose. The possible reasons for the absence of this uncoupling effect are discussed and the data are incompatible with the notion that the energy-dependent uptake of dansyl-galactoside is associated with an active transport involving a dansyl-galactoside/H+ symport. The data substantiate the initial interpretation that the energy-dependent uptake of dansyl-galactoside reflects the binding to the lac carrier not followed by transport.

(PDF 0-2 workdays service)

Order PDF Full Text


Click here to order any other PDF Full Text

Accession: 005151713

PDF Full Text: Submit

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Other references

Dauter Z., 1988: X ray characterization of single crystals of the reaction center i of water splitting photosynthesis. A new type of crystals of the reaction center I complex, RC I, of water splitting photosynthesis has been prepared from the cyanobacterium Synechococcus sp. In contrast to our first crystals (11), the new ones have a length of up to 1 mm, a thickn...

Bieri, O.; Patil, S.; Quick, H. H.; Scheffler, K., 2007: Morphing steady-state free precession. A novel concept for visualization of positive contrast originating from susceptibility-related magnetic field distortions is presented. In unbalanced steady-state free precession (SSFP) the generic, gradient-induced dephasing competes with local g...

Ogawa, Yasuo, 1999: Ryanodine receptor isoforms as putative sites for cyclic ADP-ribose. Japanese Journal of Pharmacology 79(SUPPL 1): 10P

Sharma, A. K.; Sarkar, S. K., 1957: Cytology of different species of palms and its bearing on the solution of the problems of phytogeny and speciation. The results are presented of a detailed cytological study of 50 species of palms from 28 genera, using the technique described in PB A, XXVI, Abst. 79. The chromosome numbers of the species studied are listed, 19 having 2n = 36, 22 having 2n = 32,...

Hori A., 1972: Digital simulation of carbon di oxide regulation in human breathing. Journal of the Physiological Society of Japan 34(6): 381

Xia, Y.; Arai, A. C., 2003: Differential effects of AMPA receptor modulators on subtypes of hippocampal CA1 neurons. Signal processing in hippocampal area CA1 is regulated by feedforward and feedback excitatory-inhibitory circuits in which a variety of inhibitory interneurons participate. Fast excitatory synaptic transmission throughout the hippocampus is mediat...

Jamieson, Glen S., 1991: Pacific and Atlantic blue mussel (Mytilus edulis) mortality in British Columbia. Bulletin of the Aquaculture Association of Canada. June; 912: 37-42

Escobedo-Amezcua, Federico; Garcia-Winder, Miguel; Nuncio-Ochoa, Ma-Guadalupe, J.; Gallegos-Sanchez, Jaime, 2005: Efecto de un progestageno (norgestomet) en la secrecion pulsatil de la homrona luteiniante en vaquillas Bos taurusxBos indicus prepuberes en el tropico Mexicano. The aim of this study was to determine the minimal age at which a progestagen induces ovulation and formation of normal average life corpus luteum in prepuberal heifers in the Mexican tropics. Twenty heifers Bos taurusxBos indicus of different age...

Black A.K.; Heavey D.J.; Barr R.M.; Barrow S.E.; Chappell C.G.; Greaves M.W.; Dollery C.T., 1985: The release of histamine and eicosanoids in cold urticaria. Journal of Investigative Dermatology 84(5): 443

Gorlitskiy B. A., 1969: Trace elements as indicators of geochemical stability of iron-bearing quartzites, with rocks of the Bol'shoy Krivoi Rog region as an example. Uniform concentration, result of sedimentary deposition, little affected by metamorphism.