Amino acid transport in brush-border-membrane vesicles isolated from human small intestine.
Uptake of L-alanine and L-phenylalanine by purified bursh-border-membrane vesicles isolated from human small intestine was investigated by using a rapid-filtration technique. L-Alanine entered the same osmotically reactive space as D-glucose, indicating that transport into the vesicle rather than binding to the membranes was being observed. The uptake rate for L-alanine was higher in the presence of a Na+ gradient than in the presence of a K+ gradient. In the presence of a Na+ gradient, the lipophilic anion SCN- caused an increase in L-alanine transport, whereas the nearly impermeant SO42- anion decreased the uptake of L-alanine compared with its uptake in the presence of Cl-. The uptake of L-phenylalanine into the brush-border-membrane vesicle was also stimulated by Na+. The results indicate co-transport of Na+ and neutral amino acids inthe human intestinal brush-border membrane.
D000409:Alanine / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000378:metabolism* / Q000648:ultrastructure; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D010649:Phenylalanine / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D013431:Sulfates / Q000494:pharmacology; D013861:Thiocyanates / Q000494:pharmacology
D013431:Sulfates; D013861:Thiocyanates; D010649:Phenylalanine; D012964:Sodium; D000409:Alanine