HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jentsch, T. J. Articles by Wiederholt, M. Search for Related Content PubMed PubMed Citation Articles by Jentsch, T. J. Articles by Wiederholt, M. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 261, Issue 23, 10673-10679, 08, 1986

Kinetic properties of the sodium bicarbonate (carbonate) symport in monkey kidney epithelial cells (BSC-1). Interactions between Na+, HCO- 3, and pH

TJ Jentsch, P Schwartz, BS Schill, B Langner, AP Lepple, SK Keller and M Wiederholt

BSC-1 kidney epithelial cells derived from the African green monkey are known to express a Na+HCO3- symport (Jentsch, T. J., Schill, B. S., Schwartz, P., Matthes, H., Keller, S. K., and Wiederholt, M. (1985) J. Biol. Chem. 260, 15554-15560). In the present work, 4,4- diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-sensitive 22Na+ uptake into confluent monolayers of BSC-1 is measured in the presence of ouabain (10(-4) M) and amiloride (10(-3) M) to define the interactions between Na+ and HCO3- binding and pH. Dependence of DIDS- sensitive 22Na+ fluxes on either Na+ or HCO3- can be described by Michaelis-Menten kinetics. External apparent Km for HCO3- decreases with increasing Na+ concentration (Km app (HCO3-) = 36 +/- 10, 18 +/- 5, and 9 +/- 3 mM at 20, 45, and 151 mM Na+o, respectively (pHo = 7.4)). Similarly, external apparent Km for Na+ decreases with increasing HCO3- concentration (Km app (Na+) = 73 +/- 22, 28 +/- 8, and 14 +/- 4 mM at 6, 17, and 56 mM HCO3o-, respectively (pHo = 7.4)). Vmax app remains constant within the experimental error. When data are replotted as a function of calculated NaCO3- concentration, they can be approximated by a single Michaelis-Menten equation. DIDS-sensitive uptake at constant Na+ and HCO3- displays a broad pH optimum in the range between 7.2 and 7.6. The data are compatible with the ion pair model in which the transported species, NaCO3-, binds to the transport site with Km = 15.3 +/- 4 microM. However, the data may also be fitted by either a random or ordered bireactant system. Sets of parameters necessary for these fits are given.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				A. Pushkin and I. Kurtz SLC4 base (HCO3-, CO32-) transporters: classification, function, structure, genetic diseases, and knockout models Am J Physiol Renal Physiol, March 1, 2006; 290(3): F580 - F599. [Abstract] [Full Text] [PDF]

				C. M. Sciortino and M. F. Romero Cation and voltage dependence of rat kidney electrogenic Na+-HCO-3 cotransporter, rkNBC, expressed in oocytes Am J Physiol Renal Physiol, October 1, 1999; 277(4): F611 - F623. [Abstract] [Full Text] [PDF]

				A. W. Jehle, H. Hilfiker, M. F. Pfister, J. Biber, E. Lederer, R. Krapf, and H. Murer Type II Na-Pi cotransport is regulated transcriptionally by ambient bicarbonate/carbon dioxide tension in OK cells Am J Physiol Renal Physiol, January 1, 1999; 276(1): F46 - F53. [Abstract] [Full Text] [PDF]