AJP - Gastrointestinal and Liver Physiology, Vol 262, Issue 4 609-G615, Copyright © 1992 by American Physiological Society

ARTICLES

Distinction between chloride-dependent transport systems for taurine and beta-alanine in rabbit ileum

L. K. Munck and B. G. Munck
Department of Medicine F, Gentofte Hospital, Copenhagen, Denmark.

This study describes the influx of taurine and beta-alanine across the brush-border membrane of rabbit distal ileum. The kinetics of JmcTau [concentration at which half-maximal activation occurs (K1/2) = 41 microM and Jmax = 24 nmol.cm-2.h-1] are consistent with the kinetics of taurine uptake by jejunal brush-border vesicles. The taurine carrier differs from the beta-alanine carrier by being insensitive to leucine inhibition and by the jejunoileal variation of influx along the small intestine. The K1/2 for sodium and chloride activation of the beta-alanine carrier (48 and 8 mM, respectively) differ markedly from the values reported for the taurine carrier. In addition, taurine is not transported by the beta-alanine carrier. Thus the study demonstrates that the taurine and beta-alanine carriers are separate entities, and it adds to the imino and the taurine carriers the beta-alanine carrier as a third chloride-dependent intestinal transporter of amino acids.

This article has been cited by other articles:

				B. G. Munck and L. K. Munck Effects of pH changes on systems ASC and B in rabbit ileum Am J Physiol Gastrointest Liver Physiol, January 1, 1999; 276(1): G173 - G184. [Abstract] [Full Text] [PDF]

				R. DEVES and C. A. R. BOYD Transporters for Cationic Amino Acids in Animal Cells: Discovery, Structure, and Function Physiol Rev, April 1, 1998; 78(2): 487 - 545. [Abstract] [Full Text] [PDF]