Multiple transport pathways for neutral amino acids in rabbit jejunal brush border vesicles

Bruce R. Stevens, Helen J. Ross, Ernest M. Wright

Research output: Contribution to journalArticle

224 Scopus citations

Abstract

Amino acids enter rabbit jejunal brush border membrane vesicles via three major transport systems: (1) simple passive diffusion; (2) Na-independent carriers; and (3) Na-dependent carriers. The passive permeability sequence of amino acids is very similar to that observed in other studies involving natural and artificial membranes. Based on uptake kinetics and cross-inhibition profiles, at least two Na-independent and three Na-dependent carrier-mediated pathways exist. One Na-independent pathway, similar to the classical L system, favors neutral amino acids, while the other pathway favors dibasic amino acids such as lysine. One Na-dependent pathway primarily serves neutral l-amino acids including 2-amino-2-norbornanecarboxylic acid hemihydrate (BCH), but not β-alanine or α-methylaminoisobutyric acid (MeAIB). Another Na-dependent route favors phenylalanine and methionine, while the third pathway is selective for imino acids and MeAIB. Li is unable to substitute for Na in these systems. Cross-inhibition profiles indicated that none of the Na-dependent systems conform to classical A or ACS paradigms. Other notable features of jejunal brush border vesicles include (1) no β-alanine carrier, and (2) no major proline/glycine interactions.

Original languageEnglish (US)
Pages (from-to)213-225
Number of pages13
JournalThe Journal of Membrane Biology
Volume66
Issue number1
DOIs
StatePublished - Dec 1 1982

Keywords

  • alanine transport
  • amino acid transport
  • brush border transport
  • membrane vesicles
  • phenylalanine transport
  • proline transport
  • small intestinal transport

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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