@article{8a6a350a6ae14577949881940c99c36c,
title = "Effect of pH on the transport of Krebs cycle intermediates in renal brush border membranes",
abstract = "Lowering extravesicular pH stimulated Na+-dependent citrate transport in renal brush border membrane vesicles: e.g., at pHout = 5.5, the initial rate of citrate uptake was increased 10-fold compared to parallel control experiments at pH 7.5. The same experimental conditions had little effect on succinate uptake. The influence of pH on citrate transport is a product of the extravesicular H+ concentration; pH gradients did not potentiate the effects nor were proton gradients capable of driving transport in the absence of Na+. The effect of pH is adequately explained if only the mono- and divalent species of citrate (Cit1-, Cit2-) are considered acceptable substrates for transport. The stimulatory influence of pH on transport correlated quite well with pH-related increases in the concentrations of Cit1- and Cit2-, and over the same pH range [Cit3-] was inversely related to citrate uptake. A model of the Na+-dependent dicarboxylate transport system is discussed in which three sodium ions are translocated per molecule of dicarboxylic acid.",
keywords = "(Rabbit kidney), Brush border membrane, Citrate transport, Tricarboxylic acid cycle, pH effect",
author = "Wright, {Stephen H.} and Ian Kippen and Wright, {Ernest M.}",
note = "Funding Information: acceptabiliotyf botht he - 1 and -2 specieiss an adequateex planatiofno r this observationa,s well as for the effecto f pH on citratet ransport. The basic eventsin volvedin the translocation of dicarboxyliacc idsa crosst her enalb rushb order membranaer es ummarizeind the modepl resented in Fig. 4. The couplingo f threes odiumi ons per moleculeo f dicarboxylatise b asedo n directm ea-surementso f the simultaneoufsl uxes of 14C-labelleds ubstrateasn d 22Na+,a nd is consistent with thek ineticc haracteristiocfs t hei nteractioonf Na + with succinate/citrattrea nsport\ [4\]T.h e presentr eporti ndicatest hat at pH 7.5 the pre-dominantt ransportesdp ecieso f both succinate and citrateh avea net chargeo f -2. Coupling betweetnh ef luxeso f threes odiumio nsand either a succinateo r citratem oleculere sultsi n the net movemenotf positivec hargea crosst hem embrane and is sufficientto explaino ure arlierr eporto f the electrogeniciotyf succinate/citrattrea nspor\t[ 3\]. At presentw e have insufficientin formationto suggesat possibles equencoef substratbei nding, and this topici s currentluy nderin vestigation. The authorsg ratefullya cknowledgteh etechni-cal assistancoef BruceH irayamaT. his work was funded,i n part, by USPHS grants( AM25588, NS09666a, nd AM19567)a ndby researchfe llow-ships to S.H.W. from the Kidney Foundationo f SouthernC aliforniaa ndt heN ationaIln stituteosf Health.",
year = "1982",
month = jan,
day = "22",
doi = "10.1016/0005-2736(82)90019-0",
language = "English (US)",
volume = "684",
pages = "287--290",
journal = "BBA - Biomembranes",
issn = "0005-2736",
publisher = "Elsevier",
number = "2",
}