Open AccessNa + ‐Dependent Uptake of 4‐Azidophenylalanine by Pig Intestinal Microvillus Vesicles
Author(s) -
NORÉN Ove,
SJÖSTRÖM Hans,
LARSEN Per
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07532.x
Subject(s) - labelling , alanine , vesicle , phenylalanine , lysine , chemistry , sodium , amino acid , biochemistry , membrane , organic chemistry
A procedure for the synthesis of tritiated 4‐azidophenylalanine in a radioactively homogeneous form is described. The characteristics of the 4‐azidophenylalanine uptake by pig intestinal microvillar vesicles and its interaction with the neutral amino acid transport have been studied. 4‐Azidophenylalanine is transported into an osmotically sensitive space and the transport is sodium dependent. It is demonstrated that 4‐azidophenylalanine transport is inhibited by l ‐alanine and l ‐phenylalanine but not by l ‐lysine and d ‐glucose. Likewise 4‐azidophenylalanine inhibited the initial transport of l ‐lysine and d ‐glucose was unaffected. Treatment of microvillar vesicles with 4‐azidophenylalanine in combination with photolysis irreversibly inactivated the l ‐alanine transport. Photolabelling in the presence of sodium using tritiated 4‐azidophenylalanine resulted in labelling of 10 peptides, all found in the fraction insoluble in Triton X‐100. Omission of sodium from the reaction mixture or addition of l ‐alanine did not specifically abolish labelling in any of the labelled components.