MULTIPLE TRANSPORT PATHWAYS FOR NEUTRAL AMINO-ACIDS IN RABBIT JEJUNAL BRUSH-BORDER VESICLES
MULTIPLE TRANSPORT PATHWAYS FOR NEUTRAL AMINO-ACIDS IN RABBIT JEJUNAL BRUSH-BORDER VESICLES
复制标题
DOI：
10.1007/bf01868496
复制
发表时间：
1982-01-01
影响因子：
2.4
通讯作者：
WRIGHT, EM
中科院分区：
文献类型：
--
作者：
STEVENS, BR;ROSS, HJ;WRIGHT, EM
Amino acids enter rabbit jejunal brush border membrane vesicles via 3 major transport systems: simple passive diffusion; Na-independent carriers and 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 2 Na-independent and 3 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-norbornanecarboxylic acid hemihydrate (BCH), but not .beta.-alanine or .alpha.-methylaminoisobutyric acid (MeAIB). Another Na-dependent route favors phenylalanine and methionine, while the 3rd 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 no .beta.-alanine carrier and no major proline/glycine interactions.
