Sodium-Dependent Amino Acid Transport Is Preserved in Lyophilized Reconstituted Apical Membranes from Intestinal Epithelium
✍ Scribed by Bruce R. Stevens; Robert L. Preston
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 229 KB
- Volume
- 265
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
We demonstrate for the first time that functional electrogenic Na ؉ -dependent amino acid transport is preserved for extended periods when purified brush border membranes prepared in hypotonic media are lyophilized and then rehydrated in buffer containing mannitol, NaSCN, and/or KSCN/valinomycin. Reconstituted lyophilized apical membranes from small intestine formed morphologically, physiologically, and thermodynamically normal vesicles which transported L-alanine via system B into an osmotically active space energized by secondary active transport, as measured under equilibrium and nonequilibrium conditions. The lyophilized membranes are readily prepared and stored, thereby providing a means to pool large quantities of formed vesicles that are useful in examining cloned and reconstituted native amino acid transporter polypeptides.